Understanding Anti-Aliasing

[Zappykins]

SvennoJ said:

Zappykins said:

 

I was refering to the flicker of the flourecent tubes that was lighting the screen behind the LCDs.  I figured I was seeing that flicker - it does flicker very rapidly right?

The backlight in LCD tv's don't flicker, but the lcd panel can. It depends on the quality and how well calibrated it is.
This is a very technical explanation http://www.intersil.com/content/dam/Intersil/documents/an12/an1208.pdf

LCD monitors do have flicker if brighness is controlled by pulse width modulation. Instead of the backlight dimming, it is rapidly turned on/off to darken the screen. http://www.tftcentral.co.uk/articles/pulse_width_modulation.htm (Darwin award for who came up with that brilliant suggestion)

My 1080p 52" lcd tv has a different problem, horizontal striping. Slightly different bands of brightness going accross the screen. It's not noticeable in normal viewing but when you get smooth gradients it becomes visible. It kinda destroys the easthetic of the darker levels in Journey. The tv is from 2006, so maybe it's age related, the thing is on all the time.


I looked into it a bit further and apparently most new lcd tv's use PWM now :(
I can't find a definite answer about OLED, plenty of complaints of flicker there too though, but no straight answers why.
The only true flicker free option seems to be an LCD projector with a constantly lit bulb (using a mechanical iris for dimming). There's still the possibility of the lcd panel causing flicker. (And expensive bulbs that degrade over time, nothing is perfect)

All fluorescent lights flicker.  Some more perceptibly than others. I was talking about the flicker of the backlight.  Just the backlight on by itself with no picture.  It fast, but it's flickering.

LED’s flicker too.  Some not even as quickly as a fluorescent light and it baffles me it doesn’t annoy other people.  At holiday time, some people but up those flickering lights and it keeps me out of certain places.   And the LED that is on cars and the front of the Xbox really annoy me with their flicking.

But it is fast enough I don’t notice. But it does have to be rather quick.

What is wrong with PWM?