Patent ID: 7759874
Filing Date: 2010-07-20
Classification: C03B

Abstract:
1. An apparatus for carrying out a plasma chemical vapor deposition process by which one or more layers of doped or undoped silica can be deposited on the interior of an elongated glass substrate tube, the apparatus comprising: an elongated microwave waveguide that projects into a substantially annular resonant cavity that is formed substantially cylindrically symmetrically around a cylindrical axis; wherein said resonant cavity comprises an inner cylindrical wall and an outer cylindrical wall, said inner cylindrical wall defining a slit that extends in a full circle around said cylindrical axis of said resonant cavity; wherein said microwave guide has (i) a longitudinal axis that extends substantially perpendicularly to said cylindrical axis of said resonant cavity so as to form a coaxial waveguide and (ii) a supplemental axis that extends at an angle relative to said longitudinal axis so as to form a feed waveguide; and wherein an antenna within said coaxial waveguide is movable along said longitudinal axis of said microwave guide to bisect said feed waveguide.