Self-Healing LCD - Printable Version +- HP Forums (https://archived.hpcalc.org/museumforum) +-- Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum-1.html) +--- Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum-2.html) +--- Thread: Self-Healing LCD (/thread-56583.html) |
Self-Healing LCD - bill platt - 05-08-2004 Hi all you fellow calculator hounds,
http://plattesign.net
Re: Self-Healing LCD - Arnaud Amiel - 05-08-2004 I had already see this one on a watch, but not on a calculator. Maybe I can keep some hope for my Xpander which has the same problem.
Arnaud
Re: Self-Healing LCD - Larry Corrado - 05-09-2004 I wonder if this could be a thin film interference effect. If you have two parallel reflecting surfaces very close together (with a gap somewhat less than 1/2 the wavelength of light apart), incident light can be reflected with destructive interference, yielding little or no reflected light. There would be internal reflection from the top surface and external reflection from the bottom. A 180 degree phase change takes place from the external reflection (as I recall), causing destructive interference in the two reflected rays, yielding a dark area. Perhaps there was a problem in the physical spacing of layers in the display, and, for some reason, the components got moved backed to their proper spacing. Hope this explanation is clear. Anyway, it's a possibility.
Larry
Re: Self-Healing LCD - John Smitherman - 05-09-2004 Hi Bill. My 9s had a black spot show up on the LCD shortly after I received it. At first, the black spot looked like an LCD defect. I was ready to return the calculator to HP when I noticed that the black spot starting moving around. At that point I assumed that the black spot was not an LCD defect but instead was a black speck of foreign material. Finally, out of frustration I shook the calculator vigorously and the black spot disappeared and has not returned. I hope that this helps.
John
Re: Self-Healing LCD - bill platt - 05-09-2004 Hi Larry,
Re: Self-Healing LCD - Johannes (Germany) - 05-10-2004 Hi Bill, it is unbelievable, but I experienced exactly the same phenomenon on exactly the same machine. It took about six years of moderate use until the black spot suddenly disappeared. I did not ask what the reason was, I was simply happy with it...
Johannes
Re: Self-Healing LCD - Larry Corrado - 05-10-2004 Bill: Yes, you're right: colored fringes would be expected to be visible around the outside of the area/point of actual or near contact, where the interference effects would be wavelength-dependent. I think I had something like this on one of my TIs. I'll have to keep my eyes open for it.
Regards. |