181 lines
4.1 KiB
HTML
181 lines
4.1 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<HTML
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><HEAD
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><TITLE
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>Infrared Light and Eye Safety</TITLE
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NAME="GENERATOR"
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REL="HOME"
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TITLE="Linux Infrared HOWTO"
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HREF="index.html"><LINK
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TITLE="Appendix"
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HREF="infrared-howto-p3-appendix.html"><LINK
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REL="PREVIOUS"
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TITLE="sersniff"
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HREF="infrared-howto-s-snersniff.html"><LINK
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REL="NEXT"
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TITLE="Copyrights, Disclaimer, Trademarks"
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HREF="infrared-howto-a-copyrights.html"></HEAD
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>Linux Infrared HOWTO</TH
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>Prev</A
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><DIV
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CLASS="appendix"
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><H1
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><A
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NAME="infrared-howto-a-eye-safety"
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></A
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>Appendix D. Infrared Light and Eye Safety</H1
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><P
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> This section summarizes some ideas and thoughts that were exchanged on the
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Linux/IrDA mailing list. It is not medically well-founded, and whoever has
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better evidence or some more well-founded source of information is
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encouraged to contribute it to this HOWTO.
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</P
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><P
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> The IrDA spec says that the range of IrDA devices has been limited to 1m for
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reasons of eye safety. Another plausible assumption is that power
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consumption and IR pollution/crosstalk were reasons for this limitation. In
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principle there could be danger for the eye, because infrared light is not
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registered by the eye, and thus the pupil won't close in order to protect
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the retina from bright IR light sources. This is the same situation as with
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UV light, which will cause snow blindness eventually, but in contrast to UV
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light, IR light contains much less harmful energy due to its longer
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wavelength.
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</P
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><P
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> The only legal restrictions and medical advices we were able to find on
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the web were concerned with infrared emissions of heat lamps or in the
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welding process and IEC 825-1 (CENELEC EN60825-1). This suggests that IR
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light as emitted by IrDA devices will be harmless, since even the peak
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power emitted by strong IR LEDs (ca. 300mW) is several orders of
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magnitude below the power emitted by medical IR heat lamps (up to 500W).
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For these, however, you are supposed to wear protective goggles, so
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maybe if you are looking straight into 1.000 infrared LEDs flashing at
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once, you should do so, too. The effect of infrared light is mostly
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heat, though, and not an alteration or destruction of the biological
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cell structure, such as caused by UV light. Though in the specs for the
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HP OmniBook 800 Hewlett-Packard recommends not to look directly into the
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IR LED.
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</P
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><P
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> As stated above, this discussion is only based on guesswork and common
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sense assumptions about the data found in IR LED and heat lamp specs.
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If anybody with a better medical knowledge can comment on this, please
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do so!
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</P
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HREF="infrared-howto-s-snersniff.html"
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>Prev</A
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>sersniff</TD
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WIDTH="34%"
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HREF="infrared-howto-p3-appendix.html"
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>Up</A
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WIDTH="33%"
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ALIGN="right"
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VALIGN="top"
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>Copyrights, Disclaimer, Trademarks</TD
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> |