Applications and Defects, Coated Substrates
Coated webs/sheet are manufactured in all widths and speeds. Substrates
range from “water-clear” to opaque. Coatings may also range from
water-clear to opaque. A number of general applications are described
below, together with key defects and their dominant optical signatures.
| High Quality Substrates and Coatings; Defects and Relative Optical Responses
|
|
Application |
Key
Defect
|
Dark
field
|
Bright
field
|
| |
|
|
|
|
Clear and Tinted Webs |
Streaks/Skips |
√√√ |
√ |
|
w/ Clear or Tinted Coatings
|
Substrate Scratches |
√√√ |
√ |
|
Inspection in transmission |
Contaminants |
√ |
√√√ |
| |
Gels (with cores) |
√√√ |
√√√ |
| |
Gels (without cores) |
√√√ |
|
| |
Hardcoat cracks |
√√√ |
|
| |
Coating Disturbances |
√√√ |
|
| |
|
|
|
|
Translucent Webs (diffusing) |
Streaks/Skips |
√√√ R |
√ R |
|
w/Clear or Tinted Coatings |
Substrate Scratches |
√ T |
√√√ T |
|
Inspection in transmission (T) |
Contaminants |
√ T |
√√√ T |
|
or Reflection (R) |
Gels |
√ T |
√√√ T |
| |
Coating Disturbances |
√√√ R |
|
| |
|
|
|
|
Opaque Webs |
Streaks/Skips |
√√√ R |
√ R |
|
w/Clear, Tinted & Opaque Coatings
|
Substrate pinholes |
√ T |
√√√ T |
|
Inspection in transmission (T) |
Contaminants |
√√ R |
√√ R |
|
or Reflection (R) |
Coating Disturbances |
√√√ R |
√ R |
| |
|
|
|
|
Wet Coatings |
Streaks/Skips |
√√√ |
|
|
Transmission or Reflection |
|
|
|
|
