Nidec Copal Corporation

Copal Company Limited

Nedec Copal Corporation

Takao Ogawa

Noribumi Tachihara

Nobuyoshi Inoue

Shigemi Takahashi

Ryo Sakurai

Shuji Ichinose

Yutaka Okazaki

A focal plane shutter apparatus is constructed by a light shielding blade, a fitting pin attached to the blade and an arm which is slidably engaged with the fitting pin to open or close the blade. A surface hardness of the fitting pin is higher than that of the arm. Concretely, the surface hardness of the arm is Hv300 to 600, and the surface hardness of the fitting pin is Hv450 to 1000. The arm and the fitting pin are subjected to chemical polishing treatment. Furthermore, the fitting pin is plated with nickel, chromium, palladium or rhodium. The fitting pin and arm have a substantially equal material hardness, or the material hardness of the fitting pin is higher. As the case may be, the fitting pin or arm may be plated with gold. Such an arrangement can suppress generation and accumulation of abrasion powder in the focal plane shutter apparatus assembled into a digital camera.

Focal plane shutter apparatus

A focal plane shutter has a light shielding shutter blade. A blade dowel is attached to the shutter blade. A blade arm is slidably engaged with the blade dowel to open or close the shutter blade. A surface hardness of the blade dowel is higher than a surface hardness of the blade arm. The surface hardness of the blade arm is Hv300 to 900, and the surface hardness of the blade dowel is Hv450 to 1000. The blade arm and the blade dowel are subjected to chemical polishing treatment. The blade dowel is plated with nickel, chromium, palladium or rhodium. A material of the blade dowel is a free-cutting stainless steel or a carbon tool steel, and a material of the blade arm is a carbon tool steel or a titanium material.

Focal plane shutter

A light shielding blade material is provided for an optical apparatus and has at least three prepreg sheets each being comprised of an epoxy resin of a thermosetting type as a matrix resin and containing a fiber drawn in an alignment direction within the matrix resin. These prepreg sheets are superposed upon each other so that the alignment directions of the fibers of the prepreg sheets disposed adjacent to each other cross at right angles to each other. The material has also two or more films each being comprised of an epoxy resin of a non-cured state as a base resin and containing 15 to 40 weight % of carbon black in the epoxy resin. These films are disposed to form a laminate of the prepreg sheets and the films so that the prepreg sheets contact one surface or both surfaces of each film. The laminate is applied with pressure and heat to cure the epoxy resin, such that the epoxy resin constituting the base resin of the film is diffused and integrated into the matrix resin of the prepreg sheet so that an interface between the base resin and the matrix resin disappears, and that the carbon black is dispersed from the base resin of the film to the matrix resin of the prepreg sheet.

Manufacturing method of light shielding blade material

A light shielding blade material for use in an optical apparatus is constructed by a substrate composed of a plastic film having a pair of surfaces opposed to each other. A shield coating capable of blocking an incident light is formed on each surface of the substrate. A reinforcement member is disposed on each shield coating. The reinforcement member is composed of a thermosetting resin prepreg sheet reinforced with fibers arranged in an alignment direction, and hardened to laminate with the substrate through the shield coating. A lubricant coating having a black appearance and a lubricity sufficient to suppress a surface friction is formed on each reinforcement member such that an upper layer of the lubricant coating and a lower layer of the shield coating are separated from each other by an intermediate layer of the reinforcement member.

Light shielding blade material for optical apparatus

A reflection preventing treatment is performed with respect to an edge face of a light shielding blade. The blade is composed of a film material made of a polyester, and is formed into a predetermined shape as a base piece. A flat face portion of the blade is capable of shielding an incident light, and an edge face portion is present in perpendicularly crossing to the flat face portion. An inner edge face of an aperture opening is included in this edge face portion. In order to form the blade, at first the base piece is punched from the film material in a predetermined shape. Subsequently, a chemical etching is applied to the edge face portion of the punched base piece so as to roughen the edge face portion. Accordingly, it is possible to suppress an unnecessary reflection of the incident light at the edge face portion. It is possible to evenly and efficiently roughen the inner edge face of the aperture opening by collecting a multiplicity of punched base pieces and dipping them in an etching solution.

Light shielding blade and method of manufacturing the same

A light-shielding blade material is provided that contributes to increased focal plane shutter speeds. A focal plane shutter has a front blade group and a rear blade group, each being composed of a plurality of light-shielding blades. At least one of these light-shielding blades is made of a Be&mdash;Al alloy material containing 40% by weight or more of Be, and has a thickness of 40 to 150 microns. This light-shielding blade is light in weight and high in stiffness, thereby significantly contributing the increased focal plane shutter speeds.

Method of fabricating a light-shielding blade composed of beryllium-aluminum alloy

A light-shielding blade material is provided that contributes to increased focal plane shutter speeds. A focal plane shutter has a front blade group and a rear blade group, each being composed of a plurality of light-shielding blades. At least one of these light-shielding blades is made of a Be-Al alloy material containing 40% by weight or more of Be, and has a thickness of 40 to 150 microns. This light-shielding blade is light in weight and high in stiffness, thereby significantly contributing the increased focal plane shutter speeds.

Light-shielding blade composed of beryllium-aluminum alloy for camera

A light-shielding blade for use in cameras utilizes a film of para-type aromatic polyamide for its base material. The light-shielding blade has a single-layer structure using an aramid film as its blade material. The film is added with carbon black at a ratio of 2 to 10 percent by weight relative to a total weight of the blade material. Alternatively, the light-shielding blade has a laminated structure with a plurality of aramid films stacked each other and having a thickness of 2 to 30 microns each, a total thickness being set to a range of 50 to 200 microns.

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Tokyo, Japan

Takao Ogawa