I had to laugh as I heard some old duffer chuffing on about dead pixels and the lamentable quality of modern OLED screens "Eeeeh, this never 'appened in t'olden days and the picture is no better either" he bemoaned. I suppose in some ways he was right, after all, CRT screens didn't have pixels but we did have phosophor burns which were even more unsightly and we certainly had face blemishes. Moving on to picture quality though, if our Samsung LED TV is anything to go by, I have never ever seen a picture with more startling clarity and acuity but as we know, opinions can differ.
As to the subject of blemishes ruining screens, as is often the case, the rosy tinted spectacles we use to recollect the past along with our memories often isn't what it should be in terms of accuracy...
In actuality, face blemishes were a fact of life due to the way cathode ray tubes were made and indeed many a panicking consumer thought they had a crack in their TV screen but the marks were just surface blemishes. Were this not the case, any defect would have been rewarded with implosion as the screen would have catastrophically failed under the pumping process in which the tube envelope was raised to a very high temperature and placed under a high torr vacuum which resulted in the screen surface being subjected to an external pressure of some several tons! The glassware of a typical cathode ray tube was produced by moulding and comprised of a screen, a cone and a flanged neck - all produced sepreately and then fused together to form a single unit.
To understand the face blemish phenomenon a little further, we shall look at the production and inspection process in a little detail in our next two blog entries - what a scintillating way to enter February 2013!