| 摘要 |
A coating apparatus (10) includes a chamber (12) defining a cavity (16), a diffuser (20), a vacuum valve (26), a burst valve (28), and a vacuum pump (30). In use, the chamber (12) is heated before a batch of lenses (46) to be coated are placed within the cavity (16) together with a tablet (42) impregnated with a coating substance. Air is then pumped from the cavity (16) until the pressure has been lowered to between 1x10-3 to 1x10-1 mbar (absolute pressure). The source tablet (42) is then heated by heater (38) to release a coating substance in vapour form. The burst valve (28) is then opened intermittently to allow small bursts of air to flow into the cavity (16). The diffuser (20) imparts swirling movement to the air burst as it enters the cavity (16), so that the air swirls around within the cavity thereby causing the vapour of the coating substance to be evenly distributed within the cavity and condense evenly on the lenses (46).
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