100 hz display device with very low electromagnetic emissions needed - LCD? Shielding on CRT?
Posted on 2008-11-10
I need a monitor with very low electromagnetic emissions that will refresh an image at 100Hz or higher. Why? Read on macduff, there is some detail:
I am a scientist working in the area of brain research. We are measuring neural oscillations with EEG equipment. We are looking at brain oscillations that occur when people socially cooperate with each other. We've found some - now we're developing a machine version of a human so that we can manipulate the brain rhythms with a simulated partner to better understand whats happening in the brain.
we need a low energy display device *desperately*, that fulfills certain constraints. why?
Your brain gives off very very small (microvolt range) electromagnetic signals which we can read by placing electrodes on the scalp. We'd prefer to drill them into your head to get a better signal, but apparently there are ethical issues with this and the university won;t allow it.
[skip next para if you don't care about the experiment details]
The experiment involves real-time interaction with a computer display. The subject's behavior is relayed into a computer, and a clever set of equations (not devised by me) simulate what the behavior of another human would be. The behavior of the equations is then used to drive an animation so that as the human behaves, s/he alters the simulated human, who in turn alters the behavior of the real human. we can change the behavior of the equations; hence measure how the brain reacts to different social coordination situations.
At the moment, we've had great success with this system, but we have not done any EEG (brain) recording, just behavioral recording. The brain recordings so far have been done between two real people, rather than a person and a machine.
So, we have been able to use CRT monitors. These monitors have a refresh rate of 100Hz. That means that the WHOLE system operates at 100Hz; data acquisition, recording, display and so on. And through directX, I can use the monitor refresh cycle to guarantee the timing of the whole system. This is:
CRUCIAL!! for a scientific experiment. The timing must be PERFECT. 100Hz is ok, as long as we know that everything is in sync. In an ideal world, it would be 1000 or 10000 Hz, but it is the sync that is crucial.
It could be 60 - BUT 60Hz is too slow - the human brain begins (subconsciously, in an area called V1 - primary visual cortex) to discern the frames changing. We need at least 100.
Now: the problem: CRT's give off a ton of electromagnetic radiation. And these one's are going to do it at 100Hz - exactly where we don't want it
This will screw our brain readings.
So, we need some other display technology that can refresh the screen at 100Hz or more without giving off too much electromagnetic energy,
I've asked all over the scientific community, No one knows of such a thing. I've seen LCD/PLASMA TV's that claim to update at 100Hz - but apparently the *image* is not really being updated at 100Hz.
Does anyone know of a technology, maybe even quite an expensive one, that might fulfill my needs:
100Hz+ image refresh
very little electromagnetic radiation.
this could be some kind of shielded CRT?
it need not be 100Hz refresh - it needs to be 100Hz *image update*
hoping for some expert advice; I'm clueless about display technology.