Patent ID: 8252117

Claim:
A feed system for continuously feeding measured doses of source material to a vapor deposition apparatus, wherein the source material is sublimated and deposited as a thin film on a substrate, said system comprising: a bulk material hopper; an upper dose cup disposed to receive source material from said hopper; a lower dose cup disposed in a vacuum lock chamber to receive a measured dose of source material from said upper dose cup; and, a transfer mechanism disposed below said vacuum lock chamber to receive the measured dose of source material from said lower dose cup, said transfer mechanism configured to transfer the source material to a downstream deposition head while isolating the deposition conditions within the deposition head and blocking upstream diffusion of sublimated source to said feed system, wherein said transfer mechanism further comprises a body having an inlet and an outlet, and a first cylinder aligned with said inlet and a second cylinder aligned with said outlet, said first and second cylinders having scalloped recesses defined therein, and said first and second cylinders being sequentially rotatable such that source material from said inlet is received by said first cylinder recess and transferred to said second cylinder recess with rotation of said first cylinder, said second cylinder subsequently rotatable to deliver the source material in said second cylinder recess to said outlet, said recesses rotationally offset such that said cylinders block diffusion of sublimated source material between said outlet and inlet in all rotatable positions of said cylinders.