The article on ceramic CRTs was fascinating! I had no idea that CRTs could be made out of ceramic - I always assumed they were all glass. A short excerpt: "Sc

The article on ceramic CRTs was fascinating! I had no idea that CRTs could be made out of ceramic - I always assumed they were all glass. A short excerpt: "Scope faceplates used to be round, simply because glass CRT bottles were round, and the faceplate was part of the bottle. Today, most faceplates are rectangular, to provide maximum display area; thus they require tubes that are rectangular in cross-section. In ceramic tubes, the glass faceplate is fused (or 'fritted') onto the ceramic envelope. That is, glass bottles are truly 'bottles'; ceramic envelopes are more like sleeves, or funnels, open at both ends. Such a rectangular envelope requires great structural strength; to make one of glass would mean very thick walls, thus a much heavier tube. (TV cathode-ray tubes, for example, are not rectangular, but bowed on all four sides to achieve the necessary strength. That's why your screen is the shape it is.) ... A glass bottle is spun, or blown, inside a cavity; a ceramic one is formed outside of a mold. This gives us control over the internal geometry of the tube - particularly important in post-accelerator (helix-type) CRTs. ... the large-screen CRTs required for our display units and computer terminals rely on ceramic envelopes for the necessary strength, fidelity of image, close-tolerance geometry and reasonable cost."