box

[harry a saake]

whlie having dinner with some opticians the other night, one of then brought up the subject of a so called SHADOW BOX, something you could put lenses in to show what the index was, anyone know what he was alluding to?

[MikeAurelius]

When Schott makes lens blanks, they immerse sample lenses during the melt into an oil that has the same index of refraction as the glass they are making. This allows them to determine if the lens is shifting in index, and if there are any defects such as bubbles or striae inside the glass.

That's about the only thing that comes to my mind...