COMPACT OPTICAL VIEWER FOR MICRAFICHE OR CASSETTE

摘要

In the compact microfiche reader, light from a microfiche or cassette microfilm is projected and undergoes several reflections prior to striking a viewing screen. One of the reflecting surfaces is defined by a prism sheet having a number of prisms. Light is both reflected by and passes through the prism sheet, the prism sheet thus defining a dual-function optical surface. This makes possible a more compact viewer. Several alternatives employ foldable reflecting surfaces and a foldable viewing screen to further reduce the size of the reader.