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Safety of an IR emmitter-phototransistor

  1. Apr 20, 2015 #1
    Hi!

    I'm part of a team doing an engineering project to design a device to detect eye blinking while a patient in the hospital is sleeping.

    We have tried to use TCRT5000 sensor (http://www.vishay.com/docs/83760/tcrt5000.pdf) in the prototype and it works like charm !! However, since the TCRT5000 sensor has an IR emmitter we have some safety concerns regarding the IR exposure of the eyelids (mainly, since the eyes are closed) and the eye itself when he/she blinks.

    Consequenty, we would need the following information (underlined in yellow) that we couldn't find in the factsheet:

    https://mail.google.com/mail/u/0/?ui=2&ik=d74d78cf09&view=fimg&th=14cd6af5e516b013&attid=0.1&disp=emb&realattid=ii_14cce6849d3a11a9&attbid=ANGjdJ9GGNk7f69hmRx6CRhEFg_lYW5397Sb8ONeT2yQz_d7_RETpV7hiQtR00u7DaahYoRaII3ck1OAm-dbPYjYcDMjJmBAMZTYDOlkRnjsNT5FCzU_vl7ylWBA_MQ&sz=w910-h216&ats=1429531466650&rm=14cd6af5e516b013&zw&atsh=1

    Moreover, it has to be considered that the patients will be exposed to it 8h/day for their lifetime. If you know a way to low the intensity/power of the IR emitter it would be also apreciated. All the information is provided about the sensor is provided in the link above.

    Best regards,
     
  2. jcsd
  3. Apr 20, 2015 #2
    Sorry! The image can not be seen: I need someone to tell me how to compute irradiance (W/m^2), radiant exposure (J/m^2) and radiance (W/(m^2 sr)) using the link about the sensor I provided
     
  4. Apr 20, 2015 #3
    hello gloria

    The PDF does give a Radiant Intensity of mW/sr at a test condition of forward current and duration for the IR emitter.

    Perhaps, this will help you out,
    http://spie.org/samples/FG11.pdf

    Since you are given the Radiant Intensity, and from the setup you know the distance to the target, the target area, the cosine of the angle of the normal with the target area, shouldn't you be able to calculate what you need. It could be that I have missed something, which wouldn't be all that unusual.
     
  5. Apr 20, 2015 #4
    Thanks a lot!! I will try it :D
     
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