LED Testing and Laser Testing
THIS ARTICLE IS DESIGNED TO ANSWER THE FOLLOWING QUESTIONS.
- Which standard do I use to test an LED?
- Which standard do I use to test a laser?
- Which standard do I use to test a lamp or light?
This is the situation and how it came about
Lasers and LEDs have been classified according to their hazard since the 1970’s in the standard IEC 825 (later IEC 60825).
In 2001 the standard governing the safety of laser products (IEC/EN 60825-1) in Europe (EN) and Internationally (IEC) was substantially revised and the classification system was overhauled. This resulted in the introduction of three new classes (1M, 2M, 3R) and the abolition of Class 3A. At this point the standard applies equally to lasers and LEDs.
In 60825-1:2001 the distance for the magnifier measurement condition (Condition 2) ranges from 14 mm to 100 mm and is determined by the apparent source size of the light.
In 2005 LEDs were shifted into IEC 62471-1:2005 “Photobiological safety of lamps and lamps systems”. The measurement conditions for this standard were set at 200 mm with varying fields of view based on risk group.
IEC 60825-1 was further revised in 2007 and the revisions included the removal of most LEDs from being tested under the same standard as Lasers and a change to Condition 2 meaning the magnifier condition is now fixed at 70mm within the retinal hazard region.
As 60825-1(2001) was the last standard to implicitly apply to LEDs the 2001 standard is often still used to assess LEDs as it is the most restrictive due to the potential for a short measuring distance. Additionally this version of the standard is still referenced by other standards and directives, most notable the Electric Toys Standard.
In 2014 the most recent version of the standard came out. This revised how pulse lasers were handled as well as introducing the new Class 1C. In addition the Condition 2 measurement of 70 mm was removed and now the closest distance for measurement is the Naked Eye condition (condition 3) at 100 mm
However as IEC 60825-2 “Safety of optical fibre communication systems (OFCS)” has not yet been updated it retains a condition 2 measurement of 70 mm and as such products used in Optical fibre systems must still be evaluated to IEC 60825-1 (2007).
In Addition IEC 60825-1:2014 gives scope for testing lasers under IEC 62471 if they are used in the same situation as conventional Lamps.
TO DECIDE WHICH LED STANDARD, LASER STANDARD OR LAMP STANDARD YOU SHOULD USE, PLEASE USE THE FOLLOWING FLOWCHART.