I know there was a long thread on this before. It was left unresolved though. This is what I gleaned from the thread.
Screen flicker causes switch to low alpha state. This is supposed to act as a hypnotic opener. The flicker is reduced with higher framerates hz. Flicker occurs in a CRT because the phosphor dims while waiting for the next pass of the electron gun. LCD screens don't have that flicker because the lighting is done at the pixel level by turning the grids' transistors on and off simultaneously. Videogames are another matter as the framerate of most games is 30 hz. A crt 60hz while a computer monitor is 30 to 80 khz Assuming LCD TV's are the same as monitor's and based on a few other post's, it sounds like LCD TV's are okay. I have read that the high frequency flicker of lcd's may be worse then the low frequency flicker of CRT's. I couldn't find much about LED TV. I'm not sure though. Increased resolution, brightness and colour is supposed to worsen flicker. LCD's have a higher resolution. Dim room lighting makes it worse.
Plasma Tv
Every single pixel in a plasma screen television is it's own little fluorescent light bulb. Each of those 'bulbs' flickers at around 120 Hz 100 Hz is well within the range which can be considered a "Strobe Light" capable of inducing a hypnotic Alpha state in the brain
Effects
There seems to be contrasting views on whether the brain effects are lasting. In 1969 Herbert Krugman found it took less than 1 minute of TV viewing to convert Beta waves into beta waves. When they returned the subject to reading a magazine the brains Alpha waves reverted back to Beta waves. This indicates not.
Calming oils such as lavender and rosemary produce more alpha and theta brain waves, indicative of relaxation and well-being.
Please offer your views and insight to any points I state.
Thanks
Screen flicker causes switch to low alpha state. This is supposed to act as a hypnotic opener. The flicker is reduced with higher framerates hz. Flicker occurs in a CRT because the phosphor dims while waiting for the next pass of the electron gun. LCD screens don't have that flicker because the lighting is done at the pixel level by turning the grids' transistors on and off simultaneously. Videogames are another matter as the framerate of most games is 30 hz. A crt 60hz while a computer monitor is 30 to 80 khz Assuming LCD TV's are the same as monitor's and based on a few other post's, it sounds like LCD TV's are okay. I have read that the high frequency flicker of lcd's may be worse then the low frequency flicker of CRT's. I couldn't find much about LED TV. I'm not sure though. Increased resolution, brightness and colour is supposed to worsen flicker. LCD's have a higher resolution. Dim room lighting makes it worse.
Plasma Tv
Every single pixel in a plasma screen television is it's own little fluorescent light bulb. Each of those 'bulbs' flickers at around 120 Hz 100 Hz is well within the range which can be considered a "Strobe Light" capable of inducing a hypnotic Alpha state in the brain
Effects
There seems to be contrasting views on whether the brain effects are lasting. In 1969 Herbert Krugman found it took less than 1 minute of TV viewing to convert Beta waves into beta waves. When they returned the subject to reading a magazine the brains Alpha waves reverted back to Beta waves. This indicates not.
Calming oils such as lavender and rosemary produce more alpha and theta brain waves, indicative of relaxation and well-being.
Please offer your views and insight to any points I state.
Thanks

Have you observed this effect with LCD or old TV sets, too? Or plasma only?