Difference between Frensel reflection and Total Internal Reflection

  1. What exactly is the difference between Frensel reflection and total internal reflection with regards to the efficiency of an LED? Do they both occur at the semiconductor/ air interface? I am a bit confused, thanks for the help.
     
  2. jcsd
  3. Re: Difference between Frensel reflection and Total Internal Reflectio

    Not difference - they are related.

    * Fresnel reflection: one interface reflected like a transmission line due to impedance/refractive index discontinuity

    * Total internal reflection: two interfaces spaced just at the right distance to constructively reflect or cancel, where each interface has Fresnel reflection
     
  4. dlgoff

    dlgoff 3,075
    Science Advisor
    Gold Member
    2014 Award

    Re: Difference between Frensel reflection and Total Internal Reflectio

    There's a interface between epoxy/plastic and air.

    [​IMG]

    These lenses are designed to get the light out. :biggrin:

    [​IMG]

    But they can't get it all out.

    [​IMG]


    Thanks to http://zeiss-campus.magnet.fsu.edu/articles/lightsources/leds.html for the images.
     
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