Patent ID: 7483226
Filing Date: 2009-01-27
Classification: C23C,Y10T

Abstract:
1. An ND filter of a thin film type comprising: a transparent substrate; and a light-absorbing film and a dielectric film laminated on the transparent substrate, wherein the transparent substrate comprises a resin film which can be fed at a constant speed, wherein the light-absorbing film is deposited on the transparent substrate by sputtering a target material onto the resin film traveling at the constant speed while using a mixture gas of oxygen, nitrogen, and argon as an ambient gas, and wherein the light-absorbing film is composed of 1% through 50% by weight of a metal, 30% or more by weight of a saturated oxide of the metal, and residual components composed of compounds of the metal containing a lower oxide and nitride of the metal, and has an extinction coefficient of 0.3 or more in a visible waveform range.