28 Feb
2009
28 Feb
'09
7:52 p.m.
On 28 Feb 2009 at 19:20, eric wrote:
This may be rhetorical, but why did they use that PVA
material in the
first place, given that the solution provided in the video just places
the lens over the CRT glass with nothing but air in between?
In the beginning, many manufacturers simply placed the CRT behind a
flat sheet of safety glass (my family's 1952 RCA set was that way).
The idea was to protect the viewer if the tube were to implode (had
been known to happen).
I suspect some sort of bond between a rather thin glass lens and the
face of the CRT itself comprises the needed protection (weren't the
early RCA versions of this called "Pan-o-ply"?). Without the bond,
an imploding CRT would likely shatter the lens also. So, while this
gets rid of the "cataract", I think there's a compromise in safety.
--Chuck