| 摘要 |
<p>PURPOSE:To attain a filter easily and efficiently, by forming an optical thin film on a substrate so that this optical thin film has a gradient of thickness in the transverse direction and cutting this substrate in the transverse direction or the like to attain each stripe-shaped filter. CONSTITUTION:A substrate 1 is stretched between a pair of reels 3 and 3 in a vacuum treatment chamber 2 and is run freely through a driving roll 4, and the steam of an evaporation source 6 is allowed to act upon the substrate to attain the optical thin film on the substrate 1. This thin film has such gradient of thickness that the thickness is changed gradually in the transverse direction orthogonal to the lengthwise direction of the substrate 1. A shutter 5 is provided with an aperture 5a whose opening is changed gradually in the transverse direction. The thin film is attained on the substrate 1 with a gradient of thickness in the transverse direction, and this substrate is cut in the transverse direction or the oblique transverse direction to attain each stripe-shaped filter. Thus, the filter is attained easily and efficiently.</p> |
