By combining the wavelength conversion sheet, blue LED lighting and a blue cut filter, a new lighting technique has been realized that can produce back light images using front lighting.
It’s difficult to route cables with embedding light in a moving stage, but there are times when the contrast with a reflected light is insufficient. By using the wavelength conversion sheet, it’s possible to realize back light images without any wiring, which makes stable detections possible.
The contrast for the alignment mark is insufficient, so stable detection is not possible.
The contrast obtained is equivalent to that of images captured with back lights, which improves the alignment precision.
Assume that there is no space to install a back light when performing liquid surface inspections at a filling machine and that reflected light has to be used instead. Even if the light is installed in a narrow space, back light images can be realized by wrapping the wavelength conversion sheet around the rotating object.
Due to the effect of the reflection from the target surface, it is not possible to obtain a stable view of the liquid surface.
Only the liquid surface is clearly imaged as a back light image, which makes it possible to perform stable liquid surface inspections.