Evaluation environment
Coaxial tube: Kohler illumination type / Critical illumination type
Objective lens: PEIR Plan 10X
Camera:BU406M(2048 x 2048, 5um)
Light source: SIS-150-AIR + band pass 1100nm
Inspecting object: Mirror
<Definition of the uniformity>
The average brightness in red square is defined as criteria of 100% uniformity.
<Original image / Kohler illumination type>
Pixels (2048 ,2048)
Mean of uniformity of 8 blue squares(%) = 82.20578420281981
Max uniformity of 8 blue squares(%) = 90.36996901226476
Min uniformity of 8 blue squares(%) = 76.87275048736467
Standard deviation= 5.101972294868123
<Original image / Critical illumination type>
Pixels (2048 ,2048)
Mean of uniformity of 8 blue squares(%) =81.95705301193571
Max uniformity of 8 blue squares(%) = 95.12371239487848
Min uniformity of 8 blue squares(%) =68.47193763278311
Standard deviation=10.292410912360923
<Gaussian distribution>
This graph shows that the uniformity of Kohler illumination type is so stable comparing Critical illumination type.
■Kohler illumination type
■Critical illumination type