Fitzpatrick, Cella, Harper & Scinto
Anti-reflection film and optical system using the same
 An anti-reflection film is arranged by alternately stacking a plurality of high-refractive index layers containing Al.sub.2 O.sub.3 and a plurality of low-refractive index layers containing SiO.sub.2 on a transparent substrate in turn from the substrate side to the air side, and satisfies: PA1 1.45.ltoreq.ns.ltoreq.1.65 PA1 1.60.ltoreq.na.ltoreq.1.85 PA1 0.31.lambda.0.ltoreq.d1.ltoreq.0.42.lambda.0 PA1 0.38.lambda.0.ltoreq.d2.ltoreq.0.45.lambda.0 PA1 0.20.lambda.0.ltoreq.d3.ltoreq.0.31.lambda.0 PA1 0.18.lambda.0.ltoreq.d4.ltoreq.0.28.lambda.0 PA1 0.20.lambda.0.ltoreq.d5.ltoreq.0.30.lambda.0 PA1 0.20.lambda.0.ltoreq.d6.ltoreq.0.30.lambda.0 where ns and na are the refractive indices of the low-refractive index layer and the high-refractive index layer for light components falling with the wavelength range from 190 nm to 250 nm, di (unit: nm) is the optical film thickness of the i-th layer when the high- and low-refractive index layers are counted from the substrate side to the air side, and .lambda.0 (nm) is the reference wavelength within the wavelength range from 190 nm to 250 nm. 
Canon Kabushiki Kaisha
C C
C03C C03C
inventional inventional
Kenji Ryuji Yasuyuki Hidehiro Minoru
Ando Biro Suzuki Kanazawa Otani