home bbs files messages ]

Forums before death by AOL, social media and spammers... "We can't have nice things"

   sci.optics      Discussion relating to the science of op      12,750 messages   

[   << oldest   |   < older   |   list   |   newer >   |   newest >>   ]

   Message 12,030 of 12,750   
   Phil Hobbs to All   
   large lenses for 365nm light   
   17 Apr 15 06:20:14   
   
   From: pcdhobbs@gmail.com   
      
   That's a hard problem if you want both good image quality and good image   
   brightness.    
      
   (There's a reason that projector LCDs are small.)   
      
   One approach to improving brightness would be to arrange the light source so   
   that it's already converging as it passes through the LCD, and use a smaller   
   lens. That's how old school overhead projectors work. The usual method is a   
   large Fresnel lens    
   placed just before the object (the LCD).   
      
   But unless the lens is like 10 feet from the panel, you'll probably be   
   disappointed with the image quality from a quartz singlet.    
      
   Improving image quality is more of a job. You might be able to find an old   
   view-camera lens on eBay.    
      
   What are you trying to accomplish with this? From the wavelength, it sounds   
   like something with UV epoxy or I-line photoresist. 3D printing, maybe?   
      
   Cheers   
      
   Phil Hobbs   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   

[   << oldest   |   < older   |   list   |   newer >   |   newest >>   ]


(c) 1994,  bbs@darkrealms.ca