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OT: exploring inside an LCD backlight area

For a laptop if different in a TV. Is there a specific name for those sheets of diffuser/refractor plastic. Look like a conflation of "straightened" Fresnel lens and stationary image of TV picture noise but semirandom under x30 viewing. I've never understood why no apparent unevenness of illumination over the height of the screen and still don't see why that is . Something to do with , in this case, 3 sheets of different grades and thickness of diffussion sheet?. Also anyone know how much shorter a light tube replacement you can get away with before the edges of the screen become a/ unviewable , b/ noticeably less lit as a band at screen edges

Reply to
N_Cook
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I have the same questions. It is amazig how they can take an uneven source and make it into a (almost) completely even background. I hope someone has a patent on the idea.

Reply to
hrhofmann

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I have the same questions. It is amazig how they can take an uneven source and make it into a (almost) completely even background. I hope someone has a patent on the idea.

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Is it the same structure in LCD TVs ? Is it ust a lamp on each side giving the central area the same illumination as at a side or the top or bottom of a 4 foot or more screen. ?

Reply to
N_Cook

You may already realize that newer models utilize LEDs, although I haven't actually had one of 'em apart.

I have some Sony FDL-X600 6" LCD video monitors which use a bent FL tube behind the white layer, instead of along the sides. The tube goes back ' forth widthwise with three 180 degree bends.. I don't know if there would be a way to improvise the single lamp with several smaller ones. These monitors have some advanced features that most LCD units don't have, such as a knob adjustment which electronically (not mechanically) improves the image at different viewing angles, and switching for color temperature in addition to the regularly included brightness, contrast, color and tint.

I generally like the display of LCDs for color and brightness, but watching fast motion is bad on the cheap 22" Coby that I watch sometimes.

For computer monitors, LCDs are hard to beat for compactness and cooler operating temperatures.

I don't know the special characteristics of the layers of diffusers used behind LCDs, but I can notice a slightly darker band in the center of the Coby, but only when the entire screen is at a black level (no video displayed).. otherwise, it's not noticeable.

-- Cheers, WB .............

Reply to
Wild_Bill

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