The uniformity of thickness can also be understood as roughness. In terms of the scale of optical films (1/10 wavelength as a unit, about 100A), the uniformity of vacuum coating has been quite good, and the roughness can be easily controlled within the range of 1/10 wavelength of visible light. The uniformity of thickness can also be understood as roughness. In terms of the scale of optical films (1/10 wavelength as a unit, about 100A), the uniformity of vacuum coating has been quite good, and the roughness can be easily controlled within 1/10 of the wavelength of visible light. The uniformity of thickness can also be understood as roughness. In terms of the scale of optical films (1/10 wavelength as a unit, about 100A), the uniformity of vacuum coating has been quite good, and the roughness can be easily controlled within 1/10 of the wavelength of visible light. The uniformity of thickness can also be understood as roughness. In terms of the scale of optical films (1/10 wavelength as a unit, about 100A), the uniformity of vacuum coating has been quite good, and the roughness can be easily controlled within 1/10 of the wavelength of visible light. The uniformity of thickness can also be understood as roughness. In terms of the scale of optical films (1/10 wavelength as a unit, about 100A), the uniformity of vacuum coating has been quite good, and the roughness can be easily controlled within 1/10 of the wavelength of visible light. The uniformity of thickness can also be understood as roughness. In terms of the scale of optical films (1/10 wavelength as a unit, about 100A), the uniformity of vacuum coating has been quite good, and the roughness can be easily controlled within 1/10 of the wavelength of visible light. The uniformity of thickness can also be understood as roughness. In terms of the scale of optical films (1/10 wavelength as a unit, about 100A), the uniformity of vacuum coating has been quite good, and the roughness can be easily controlled within 1/10 of the wavelength of visible light. The uniformity of thickness can also be understood as roughness. In terms of the scale of optical films (1/10 wavelength as a unit, about 100A), the uniformity of vacuum coating has been quite good, and the roughness can be easily controlled within 1/10 of the wavelength of visible light. The uniformity of thickness can also be understood as roughness. In terms of the scale of optical film (1/10 wavelength as a unit, about 100A), the uniformity of vacuum coating has been quite good, and the roughness can be easily controlled within the range of 1/10 wavelength of visible light