Quote:
Originally Posted by newday07
you are wrong, ir and uv are different things. We need a few minutes of UV exposure per day to synthesize vitamin D.
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UV is the major worry when considering damage to your eyes. The tests that I've seen discussing IR damage to the eye were using sources with power levels well above those generated by the LEDs in an ereader's IR touch screen and with the sources aimed directly at the eye. A quick calculation based on the output of the LEDs in one touch screen model, you would get about 0.06% of the IR compared to looking directly at a 40W incandescent lamp at a distance of 5 metres. This calculation involved assuming 80% of the IR was reflected off the screen towards your eye and a reading distance of 20cm and that 50% of the energy used by an incandescent lamp is emitted in the IR-A and IR-B area. I could find no real numbers of how much of the IR from a IR touch screen is reflected off the screen so did a wild eyed assumption for the 80% reflectance (well above the 44% for an eInk Carta screen).
So while you are getting that UV exposure each day, make sure you are wearing a good pair of UV opaque sunglasses.