Page 139 - Lasers and IPLs in Medical/Aesthetic Applications v1.2
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Chapter 1 – Fundamentals of Medical/Aesthetic Lasers and IPLs v1.2
Appendix 5 – Calculating the Optical Density of your Laser Safety Glasses
We found a very useful graphic from Laser-Professionals.com which should help to explain how to calculate the optical density required for your laser glasses:
Figure 64: Optical density of laser safety eyewear
The Optical Density is how ‘dense’ your safety glasses are for particular wavelengths. In other words, how much they prevent those wavelengths from reaching your eyes.
We typically use a base-10 logarithm scale to determine this number. You can see from the above image that an OD of 3 ‘allows’ a transmission of only 0.1% of any light of this wavelength ( = 0.488 m = 488 nm) through the glass, while an OD of 6 only allows a transmission of 0.0001% through! Click here for a short video on this topic.
IMPORTANT – The Optical Density is ONLY valid for the particular wavelengths stated!
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Chapter 1 LEVEL A Fundamentals of Lasers/IPLs
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