D.1 Material and equipment
An adjustable light souce to set the ambient light in the inspection room at 200lx.
The inspection system shall be as shown in Figure D.1. The inspection source shall be of 400 lm minimum, for example a fluorescent tube of 15 w or a 40 w incandescent clear lame where the eye of the observer is completely shaded from the direct view of the source.
D.2 Evaluation methodology
Each side the lens shell be evaluated independently according to the following procedure.
a) Rinse the lens with water , and wipe it dry ;
b) Set the ambient light source to obtain a lighting of about 200 lx ;
c) Carry out the lens inspection without the aid of magnifying optics ;
d) As shown in Figure D.1. position the lens at an angle approximately 45 with the surface , 300 mm from the light source , against the matt black background ;
e) Adjust the angle to observe the reflection from the lens surface.