Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A light diffusing device for obtaining a surface uniform in the brightness by using a luminous flux narrow in the radiating angle comprising a flat smooth transparent base plate having a favorable transparency and including a luminous flux incident area defined on one side surface, a conical concavity formed on the other side surface opposed to said one side surface, aligned with the luminous flux incident area and having a bottom area at least equal to said area and light diffusing reflecting means provided on all the side surfaces except the above mentioned other side surface. Said luminous flux incident area is used as a connecting part with the end portion of a light guide or a containing section for a light source. The above mentioned other side surface serves as a displaying surface for such display medium as of words or signs or as a luminous surface for introducing lights of a uniform brightness into a plurality of light guides.

Abstract: The light diffusing device for illumination purpose includes a light source, a thin transparent base plate having a front illuminating surface and a rear surface and arranged with its side edge adjacent to the light source so as to receive light therefrom and a light reflecting plate located adjacent to or in contact with the rear surface of the base plate.