22 Nov
2010
22 Nov
'10
10:03 p.m.
On 22 Nov 2010 at 15:39, Jim MacKenzie wrote:
Some people are sensitive to flicker, and most LCD
monitors, from what
I understand, are backlit by fluorescent light, which does have a
flicker. In particular, people who are prone to migraine headaches
often find that flickering can induce or worsen headaches.
(Fluorescent lights don't bother me, but rapidly flashing lights as
seen in occasional movies can drive me nuts, and even looking at paint
test patterns on a highway as I drive by can be very bothersome. I
don't get headaches from them, but it is very uncomfortable to look at
these things.)
Of course, the refresh rate of CRT monitors can be an issue too, but
if it's high enough, it might no longer be detectable to a person.
Ever pulled an LCD monitor apart to see what was inside? The
backlight is driven from a high-frequency inverter (tens of KHz),
while a CRC vertical retrace is 80-90 Hz at best.
I'm very sensive to flicker--if I drive by a house with a
conventional CRT TV and one with an LCD TV, I can tell the difference
even with the curtains drawn because of the amount of flicker
displayed by the CRT. Similarly, I can immediately tell, from blocks
away, who's using LED Christmas tree lights by the flicker.
I used to be able to tell LED traffic signals by the amount of
flicker visible, but that's changed in the past few years, so that
said signals appear to be nearly flicker-free.
While the color rendition appears to be better on a CRT than on an
LCD screen, the CRT displays flicker and a certain amount of
fuzziness.
--Chuck