A projection optical system that projects a pattern on a first surface onto a second surface, and has a numerical aperture of 0.85 or higher includes an optical element, and an antireflection coating applied to the optical element, the antireflection coating including plural layers, an end layer having a refractive index of tan { sin.sup.-1(NA)} or greater, where NA is the numerical aperture of the projection optical system.

 
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< Lens barrel incorporating the linear guide mechanism

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> Integrated artificial and natural lighting system

> System for projecting an image using narrow band light sources

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