It is intended to injection mould a (multifaceted) polycarbonate lens
-for a non imaging application. The 'lens' is about 10in square.
Previous experience from many moons ago with moulded polcarb lens' gave
problems of dispersion due to the internal stresses.
Attempts to anneal the polycarb lens at that time were not very
successful and a glass lens was used since time was very pressing..
This application is less stringent but is there a practical way of
annealing out the internal stresses caused during the moulding process?
probably better to choose a different material such as acrylic, but
longer mold cycle times will help some
Paul Mathews
Re: How a [Canon] lens is made: ... Have you watched the video?... The annealing step is necessary to ... The larger the lens the more difficult this is. ... If pressing, annealing, and polishing are all that is required why do ... (rec.photo.digital.slr-systems)
polycarb lens problem? ... It is intended to injection mould a polycarbonate lens... The 'lens' is about 10in square. ... problems of dispersion due to the internal stresses....annealing out the internal stresses caused during the moulding process? ... (sci.optics)
Re: geometric optics ... The outer surface... of the flint lens is plane. ... contribute to dispersion,... Or to put it another way, the central radius of curvature has ... (sci.physics)
Re: geometric optics ... of the flint lens is plane. ... contribute to dispersion,... Or to put it another way, the central radius of curvature has ...glass slope into a 5 degree deviation inside the glass. ... (sci.physics)
Re: Are primes brighter and sharper than wide open zooms ... the number of cemented pairs in any lens is ... If two lenses in a group were cemented together for their entire ... A positive lens of low dispersion glass is cemented to a weaker negative lens of high dispersion glass. ... The reason for cementing them is to reduce surface reflections; the cement used has a refractive index as close as possible to that of the glasses used. ... (rec.photo.digital)
