hmm, well i'm looking at a new 21.5" iMac as we speak, and from what i can determine (by tapping on the screen surface), it sure sounds & feels like some type of clear plastic or polycarbonate, not real glass.
however, according to
wikipedia, both models use glass covered screens.
when i received the 27" iMac with the broken screen, i didn't bother to remove the protective film or examine the screen close-up, so you may be right... it might be glass on the 27" model. which would be a good thing, imo, since glass has superior optics (to plastic) and would result in a noticeably better quality display (aside from the shipping damage, of course).
so, if both models (21" & 27") use glass over the display panel, how come my 21" iMac
seems to be plastic?
maybe Apple changed the specifications, from glass to plastic, after realizing the machines were arriving at their destinations with cracked screens??
btw, i share your lack of enthusiasm for glossy screens (i prefer matte), however, i have to admit, the only time i actually notice any reflections on the iMac screen is when the display is off (no image on the screen), otherwise it looks pretty darn good, there are no annoying/distracting reflections while the machine is in-use. although, i'm still acclimating myself to Apple's wonky font rendering/smoothing technology (my eyes/brain are accustomed to ClearType), so the fonts on the iMac look
fuzzy to me (not crisp & well defined like ClearType) especially when i first began using the machine... but i'm learning to live with the 'fuzzy fonts' (overlook it actually).
there is also something odd about the way LEDs light up different areas of the screen. images with deep shadows are sometimes not properly rendered, they end up looking just black (the details are lost). and the colours on the new 21" iMac are a bit over-saturated, red in particular. apparently, LED backlighting does have some peculiarities that can cause certain images to not be accurately reproduced.
for example, whereas traditional fluorescent backlighting illuminates ALL the pixels uniformly, LED backlighting is arranged in a matrix across the entire area of the display panel, so only selected areas of the screen are lit up at any given moment, depending on the image being displayed. in other words, backlighting is turned on only when/where it is needed, saving power and producing the deep blacks that everyone loves... but then the algorithms used to light the LED matrix, varying the brightness levels in real time, have to be sophisticated enough to reproduce more complex (darker) images, without dimming the LEDs too much, causing loss of detail in the shadows, etc.
that said, display technology is not my field of expertise, so maybe someone else with more knowledge on the subject would like to jump in here...
i know one thing, IPS display panels are far superior to the more common TN (twisted nematic) types. like the new iMacs, my aging thinkpad has an IPS panel, and it still looks way better than even the best TN panels on the market today.
thoughts?