The explanation is somewhat complicated but I'll do my best.
What sort of emissions would be coming from the front of the screen? UV? it would be fairly less compared to a desktop LCD monitor one would guess?
The emissions I'm talking about are Radio Frequency (RF) emissions - the same type that your radio or TV pick up.
The display itself radiates RF frequencies together with harmonics into the UHF range (1GHz +) and because there is nothing to stop them from being transmitted (or radiated), they will come out of the front of the screen.
How does the metal casing work
Metal acts like a shield, reducing and even stopping those same RF emissions from being transmitted out of the metal casing.
This shielding is dependent on how good the grounding is, and without any or with poor grounding, it could in fact act like a crude aerial (the same as your TV aerial for instance) and could in fact cause emissions from it.
in the desktop keyboard there is a metal plate underlayed below the circuit sheet, and i can feel a slight buzz in the hands while using it. once i removed the metal plate and replaced it with a stack of papers, it was a fair bit less. maybe that metal plate was conducting the emf from the keyboard pcb to the whole keyboard. removing it might have worked in the sense that pcb is radiating via air only in a much more limited area(around the lights only).
I cannot comment on what the 'buzzing' is in your hands and your comment about the metal keyboard plate could be acting as an aerial.
What I would say is again is that all Thinkpads will have been tested by every country they are sold in to make sure (amongst other things) that any RF emissions are at safe levels.
Also the levels we're talking about are miniscule and would not I imagine be detectable or harmful to the user.
Also it does have to be said that the buzzing could be mechanical vibration that is transmitting through to your fingers. Adding paper could be damping the vibes.
I have a feeling there's a recent post about buzzing on Thinkpads - maybe do a search.
i was under the impression that running the laptop on batteries would be totally clean so far, except ive not got the chance to try it out because of a dead battery.
Because there are crystals and frequency generating circuits inside every laptop, there will be radiated emissions regardless of whether the laptop runs on batteries or mains.
The difficulty with batteries is that there is no potential path to ground via the mains adaptor so reducing the emissions has to be combination of containment - ie metal shielding, and good circuit design to reduce the level of the frequency generating elements.
Also some of the AC adaptors are two wire mains live and neutral with no earth, so with no earth the laptop design has to rely on the above design elements.
Use is personal, just to err on the side of caution/safety. Plus i’ve noticed while using the palm rest for typing for 30-40 minutes the buzzing in the palms and a slight stiffness in the joints and slight swelling of the digits which vanishes fairly fast away from the computer.
I've commented on the above. What I do suggest is using an external USB keyboard which will take your hands away from the laptop body itself.
Please keep this in perspective - once again the radiated radio signal emissions will be tiny and its very unlikely to be those which are causing you these problems.