Originally posted by: Loobusk
I had the 955df.. P.O.S.! It's a fake flat screen.. LOOK CLOSELY and you'll see that it's a regular tube monitor with a plastic face to make it look flat.. I love samsung but their NF lines are the good ones, not the DF... For $200 i suggest getting a REFURB sony FD trinitron.. Picked up a 21" refurb E500 for around $180 shipped.. INCREDIBLE monitor.. My 955df eventually turned green and blurry with time - i noticed that problem with other cheap monitors..
lol, what b.s
Taken from a review of the 753df - the 955df's 17" brother:
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Y'see, the 753DF is probably the flattest looking CRT monitor I've ever seen. But the front of it actually has a curved back face. Which is why it looks so flat.
Pay attention, class. I will be asking questions later.
Just because the front of a monitor is flat doesn't mean that the actual picture-generating phosphor-coated inside of the front glass is flat, too. The picture you see on your monitor is created by little dots of phosphor glowing when they're hit by a scanning electron beam, and the light passes through the quite thick front glass, and whatever fancy multi-layered coatings the manufacturer's put on the screen, before it gets to your eyes.
CRT glass has to be quite thick, because monitors are great big vacuum tubes. They don't need to be built very solidly just to stop atmospheric pressure from crushing them outright, but if you want to make sure they won't implode spectacularly when they're scratched and then dropped, you have to engineer in a big safety margin. Which means lots of glass. The flatter you make the front face of the monitor, the less like an optimal pressure-resisting sphere it'll be. Shapes that don't resist pressure well need even more glass, in order to be strong enough. Curving the inside of the front glass lets monitor makers deliver a flat front, while reducing the amount of glass they have to use. It also makes it easier for the electron-beam apparatus to focus on the screen. Since the three electron beams (one each for red, green and blue phosphor dots) all originate at the back of the tube, it's easiest to keep them focussed if you curve the front glass so the distance from electron gun to screen remains more constant as the beam scans.
The flat-front, curved-back design is isn't a bad compromise, by the way, even if the back curvature is enough that the "flat" monitor's image doesn't look any flatter than that of a plain curved-front monitor.
Flattening the front glass means the monitor reflects less of the room behind it, which makes it easier to set the screen up where you won't get distracting reflections of lights and windows and so on. Reduced reflections are a big plus for flat screens. Though, again, there's really not a huge amount of difference between a truly flat screen and a slightly curved one.
But let's say you've engineered a monitor with no internal curvature at the front. Now you hit another problem. If you make a monitor whose front panel is essentially just a thick piece of plate glass, flat on both sides, the darn image won't look flat. It'll actually look as if the monitor is slightly concave - with the edges closer to you than the middle.
This is because of the refractive index of the glass - the amount it bends light, when that light enters or leaves the glass at an angle to the interface between the glass and the air.
Refraction's what makes a saucepan full of water look shallower than it is, when you look at it from an angle. In the same way, refraction in the monitor glass makes the phosphor layer look closer to the front of the glass than it really is, when you look at it at an angle - as you do, if you're sitting with your face lined up with the middle of the screen, and then look at the screen edge.
Monitor glass is "leaded" - lead oxide's added to the molten glass in place of the calcium oxide used in ordinary soda-lime glass. Basically, this means CRTs are made of a kind of low-grade lead crystal. Lead crystal's used for expensive cut-glass ornaments because it's got a higher refractive index than plain silica glass. The higher refractive index makes it split light more dramatically into a spectrum than plain glass can.
In monitors, the glass is leaded to stop the X-rays produced by the electron beam hitting phosphor and other internal components from making it out to the computer user. The higher refractive index is a side effect, and an unwanted one. It exacerbates the apparently-concave problem, if the phosphor side is actually dead flat.
For this reason, the phosphor side of the DynaFlat tube isn't flat. It is, rather, curved just enough that when you're sitting in front of the monitor, the display itself looks near-as-dammit to dead flat.
That's not the end of the DynaFlat tube's interesting-ness, though.
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