A photo-chemical vapor deposition ("photo-CVD") apparatus has exchange apparatus of optical window and method of exchanging optical window therewith. There photo-CVD apparatus has exchange apparatus of optical window which can replace an optical window blurred by attachment of materials...http://www.google.com.au/patents/US5810930?utm_source=gb-gplus-sharePatent US5810930 - Photo-chemical vapor deposition apparatus having exchange apparatus of optical window and method of exchanging optical window therewith 
