ELECTROMAGNETIC WAVE CUTOFF FILTER, MULTIFUNCTIONAL FILTER, AND IMAGE DISPLAY

PROBLEM TO BE SOLVED: To provide an inexpensive electromagnetic wave cutoff filter of aluminum in which an improvement is made in smoothness of a contour of a pattern formed by chemical etching, as compared to defective smoothness in the prior art which is caused by using low-cost aluminum for a metal pattern material instead of copper, and to provide a multifunctional filter and an image display at low cost using the electromagnetic wave cutoff filter. SOLUTION: The electromagnetic wave cutoff filter includes an aluminum pattern 2 as a metal pattern on a transparent substrate. The thickness t of an aluminum oxide film on at least its upper surface (on the side where the pattern 2 is formed on the transparent substrate) is 0 ≤t≤13 . A relation of an average value L of a line width of the pattern 2 and variations ΔL (3σ) are represented as (ΔL/L)×100≤50%. The multifunctional filter is obtained by laminating the electromagnetic wave cutoff filter and an optical filter. The image display is configured by disposing the electromagnetic wave cutoff filter or the multifunctional filter on the front side. COPYRIGHT: (C)2010,JPO&INPIT