Features of configuration Purpose Effect
a. LED light source   (Visible、UV) ① Long life in a small power   ②③ Exchange-free ④
(Metal halide light   source+Linear fiber)*  (High illumination)*
b. Plate-shaped rod   prism ① Uniform line light source  Efficient illumination
c.   Fresnel lighting system ⑤            (Fresnel lens+Apodizing filter) Uniform linear lighting  Efficient illumination
d. Partially   coherent illumination ⑥ Improved resolution of the   imaging lens ⑩ High contrast imaging ⑪⑫
e. Sigma aperture of the collimator lens ⑦⑧ Deep depth of focus⑩ Higher detection rate of defect and waste
f. Aperture of imaging lens ⑨
g. Correspond to the various   lighting methods Line transmitted illumination Illumination for transparent object
Defect inspection、Waste   inspection
Line reflected illumination Oblique reflection image
Line epi-illumination Perpendicular reflection image
h. Various imaging lens ⑬ Line imaging Correspond to ‘-0.3X~-2.4X imaging
i.   DALSA line sensor camera standard
Light beam from some LEDs put on the   left entrance surface of the plate-shaped rod prism, by repeating total   reflection at that side
, makes the uniform illumination of   right emitting surface of the prism.
The light source should just supply   the light flux which contributes to image formation. Several watts LED may be   sufficient.
Conventional fiber diffused   illumination systems require a metal halide light source of several hundred   watts.
For using a long-life LED, light   sourcereplacement is not required.
The light beam passing through the   circular sigma aperture of collimator lens, it becomes a rectangular shape   gradually,
make a uniform rectangular   illumination area on the object plane after being refracted by the Fresnel lens.
Since the Sigma aperture of   illumination sysytem and the aperture of the imaging lens are conjugate, Fresnel illumination system   allows 
the partial coherent illumination.
Rectangular light beam from the   plate-shaped rod prism’s exit surface, are rounded by sigma aperture and   collimator lens consisting of multiple lenses .
Since there is no Sigma AP Stop to   be conjugate, coherent illumination is not possible in the fiber diffuse   illumination system.
Rectangular light beam illuminating   the object plane, become circular at the stop of imaging lens.
For example, the use of partially   coherent illumination by reducing the aperture of illumination,
and illuminated with light beams   directly only the center of the aperture of imaging lens,
then resolution enhancement of 1.5   times, focal depth of 2.0 times can be obtained.
 【Refer to the after-mentioned experimental   data】
Only light beam contributing to   imaging present in the imaging lens, the imaging contrast degradation caused   by flare does not occur.
Fiber diffuse illumination system   degrades imaging contrast by large angle light beam reflected by the imaging   lens barrel.
The light beam passing through the   circular aperture of the imaging lens, bocoming a rectangular shape   gradually,
makes an object image on a   rectangular image plane.
[Conjugate relation of the   rectangular image]
(Emitting surface of the plate-shaped rod prism)
(Object plane) (Image plane)
[Cnjugate relation of the circular   pupil]
(Ilumination sigma aperture)
(Imaging lens   aperture)