Ask Slashdot: Does LED Backlight PWM Drive You Crazy?

jones_supa writes "I would like to raise some discussion about a hardware issue that has increasingly started to bug me: backlight flicker, from which many LED-backlit monitors suffer. As you might know, the backlight and its dimming is driven by a pulse width modulated square wave, essentially flicking the LEDs on and off rapidly. Back in the CRT days a 100Hz picture was deluxe, due to the long afterglow of the display phosphor. LEDs, however, shut off immediately and my watering eyes and headache tell that we should be using frequencies in multiple kHz there. Unfortunately we too often fall behind that. As one spark of hope, the display review site PRAD has already started to include backlight signal captures to help assessing the problem. However with laptops and various mobile gadgets, finding this kind of information is practically impossible. This issue sort of lingers in the background but likely impacts the well-being of many, and certainly deserves more attention." So do LEDs bother your eyes? I think CRTs gave me headaches far more often than has any form of flat panel display, at least partly because of the whining noise that CRTs emit.

Comments

Is it only the monitor?

[barc0001]

One thing I do know was/is a problem with monitors and eyestrain has to do with fluorescent lighting in the room. We can't see it with the naked eye, but the fluorescents are also flickering at 60hz and I've had it happen in the past that if the CRTs I was using were out of sync, (running at 75hz or similar) after a while I'd get weird eye strain from something we can't consciously perceive but our eyes still try to correct for. I usually solved the problem by either setting the CRT sync rate as high as it would go or syncing it to 60hz, or preferably getting rid of the fluorescent lighting completely in my workspace when possible. Maybe a similar effect is at work here?