Page 223 - Chapter 3 - Laser/IPL Hair Removal

Chapter 3 – Fundamentals of Laser/IPL Hair Removal 2nd Edition
Figure 118 - Typical filters for an IPL system
re-emits them as longer wavelengths. This type is only used in a very small number of IPLs.
The figure above shows a range of absorption filters which each block a portion of the spectrum. The numbers refer to the lower limit of the transmitted range. Hence, in most IPL systems these filters will allow all wavelengths from the referred numbers up to 1200 nm. I.e. the 2nd filter down will allow all wavelengths between 530 nm and 1200 nm to be transmitted through to the skin. The energy in the waveband below this (400 to 530nm) is absorbed by the pigment in the filter, causing it to be heated during each pulse.
An important part of any clinical treatment is the careful selection of the filter. You must follow the guidelines closely to ensure you are using the correct filter otherwise unwanted results may occur.
How much energy is in each waveband?
We know that each filter blocks a certain amount of light energy, but how much actually gets through to the skin? We devised a program to calculate these energies based on an accurate measurement of the spectral output from a Xenon lamp.
________________________________________________________________________ 223 Chapter 3, Ed. 2.0 Laser/IPL Hair Removal
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A typical set of filters supplied with an IPL unit.
In this particular case, the filters may be used for various conditions:
480 nm May be used for benign pigmentation and active acne
530 nm May be used for all blood vessels
640 nm May be used for darker hair in lighter skins
690 nm May be used for darker hair in darker skins