120Hz LCDs

[Diagrafeas]

Does anyone know if/when 120Hz LCDs with be available? What about LED backlight? Are these things to much to ask? Should we wait for SED instead?

 

[LittleNemoNES]

::shakes magic 8 ball::

"Better Not Tell You Now"

 

[ImDonly1]

As LCD's do not rely on refresh rate... I do not see how 120Hz LCD's would have any use over the current ones?

 

[darkswordsman17]

Originally posted by: ImDonly1
As LCD's do not rely on refresh rate... I do not see how 120Hz LCD's would have any use over the current ones?

There's much more to it than that. Some of it has to do with syncing with the video feed and things like that. I recall reading an article by some tech site that got to spend a week with I think a 100hz monitor and for some things (gaming I think) they really liked it while for others (movies) it wasn't so good (they said it seemed almost too realistic in how things moved and was disconcerting because of this).

Unfortunately I can't recall who it was (extremetech or maybe sharky come to mind but I don't know if it was either of them).

 

[lambchops511]

they will appear soon (expect this summer)

 

[Elderly Newt]

Originally posted by: ImDonly1
As LCD's do not rely on refresh rate... I do not see how 120Hz LCD's would have any use over the current ones?

They do, just not in the same way as CRTs. Im pretty sure a 60hz refresh rate means each pixel receives an update 60 times each second, and they dont all receive an update at the same time - its done in lines like a CRT, which is why you can still get tearing with an LCD.

 

[xtknight]

When you send an LCD 75 Hz, it is discarding every fifth frame (60/75=.8, LCD (least common denominator): 4/5=.8).

(highlight indicates frame removed by LCD's processor)
60 Hz transmission: AA BB CC DD AA BB CC DD
75 Hz transmission: AA BB CC DD EE AA BB CC DD EE

So when you send 75 Hz to an LCD today you will actually get an image that jitters.

What is common called a "120 Hz" LCD is one that inserts a black frame (BFI) or strip in a 60 Hz signal.
(XX indicates a black frame)

60 Hz transmission: AA BB CC DD AA BB CC DD
60 Hz transmission (with BFI): AA XX BB XX CC XX DD XX AA XX BB XX CC XX DD

The XX frame lasts for 16.6 ms, that's enough time for your eyes to wipe themselves of the last image. That results in an image with less blur/afterglow effect. Your retinas are at work here creating blurriness and CRTs scan the screen out with black every 16.6 ms (@ 60 Hz). The BFI (black frame insertion) technology turns off the backlight for 16.6 ms. (one frame). This does decrease overall brightness since the backlight is being modulated like this (not really a problem since LCDs are very bright to begin with).

BenQ's BFI tech actually is a strip of 16 backlights on the back of the panel. Each of the 16 is blanked out consecutively to emulate the raster scanning motion of a CRT. And, plus when only a portion of the image is being flickered, the effect isn't nearly as noticeable as the whole screen flickering.

Whether true "120 Hz" LCDs (ones that take in 120 frames per second) will arrive is unknown. But that term most common refers to the above technology (BFI).