The defect detection unit basically
consists of 1) a light receiver (Camera Unit), 2) a
light source (Lighting Unit), 3) a signal processor
(SPU), 4) a marker or a labeller, and 5) an encoder.
The light receiver is a camera with a CCD line sensor,
and the light source is usually such as a fluorescent
lamp. There are several lighting methods: transmission
mode, diffuse reflection mode, specular reflection mode,
and a mode which uses a combination of the others.
First of all, the light from the projector illuminates
the material to be inspected so that the unit can detect
defects. The light reflects on the material to be inspected
and reaches the light receiver (camera), where the light
is converted into electric signals. The electrical signals
are transmitted to the signal processor, and then via
exclusive detection and judgment circuits, any defects
are recognized. When a defect is detected, the unit
activates the marker, alarm, rotating light, printer,
etc. and indicates the occurrence of the defect, for
example by displaying the defect image on the operator
screen. Nowadays the defect detection unit is regarded
as a more advanced system, not merely to detect defects
but to provide information to the following processes
(for example to a slitter and re-winder machine) to
enable analysis of the causes of defect occurrence.
The systems are continually evolving so they become
even more important in quality enhancement and improvement
of product yield.
For more information and specification, please contact