To enhance the nondefective rate of a carbon fiber-reinforced resin plate material and light shielding blades, to reduce the cost and to inexpensively obtain an ultra-high speed shutter of ≥1/8000 second having high durability by forming rugged mesh patterns of a specific pitch on the surface of the light shielding blade plate made of the carbon fiber-reinforced resin having a specific plate thickness.
The rugged mesh patterns of the prescribed pitch are formed on the surface of the light shielding blade of the light shielding blade plate made of the carbon fiber-reinforced resin having 50 to 200μm plate thickness. The pitch of the rugged mesh patterns is 50 to 500μm. The blade plate is constituted by laminating ≥3 layers of plural prepreg sheets 3 formed by impregnating carbon resin 1 aligned in one direction with resins so that the respective fiber directions intersect orthogonally each other and are made symmetrical with respect to plane. As a result, the unbalance of the internal stresses occurring in the nonuniformity of the resin distribution of the outermost layer are ameliorated even for the sheets in which the nonuniformity of the resins exist by forming the rugged mesh patterns of such pitch on their surface, and the flatness of the light shielding blade is thus improved.
HASUDA MASANORI
KANAMURO MASAYUKI
