Metalized Optical Windows
the perimeter solderable metal layers to optical windows is what we do......... not all that we do,
but almost all that we do.
It is certainly the lion's share of our business......not a sideline.
The front end of the metalizing process involves applying a protective cover over the clear
aperture. The covers are usually made from Corning Microsheet glass.
We make the glass masking
covers to the match the size specified on your drawing, assuming a machining tolerance of +/- .002" We also have
a large inventory of these covers on hand from which we can draw. These covers are reusable, so in most cases we will have
the right size in stock to match your clear aperture. Placement accuracy (concentricity) of the masking cover on the optical
face is typically .002" to .003" TIR.
For the highest possible reliability of the
metals system, it is best that the metals be deposited only onto the substrate material, and not overlap
on top of the anti-reflection coating, but that is not always practical. We can and do apply our metals on top
of AR coatings, usually with no issues whatsoever.
There are basically
two options when selecting the metals for your solder band, those being,
a) Cr-Ni-Au, and
There are other choices, most certainly, but these
two schemes are, by far, the most common. Of these options, the Platinum scheme is the more reliable, if for no other
reason than it having a virtually unlimited shelf life, whereas the Nickel scheme, normally, will have a shorter
shelf life. But the better reason for choosing Platinum over Ni lies in it's soldering characteristics. Platinum
is dissolved by the solder at a much slower rate than is Nickel, meaning that it will tolerate a longer dwell time in the
liquidus phase of Sn rich solders before showing any sign of dewetting. We have also found that we are able to
reflow the Platinum scheme several times, if necessary, without compromising the joint.
Some of our Pt customers prefer not to have any gold top coat, as the gold can form brittle intermetallic compounds
within the melt.
Every project is always a little different.
Please feel free to call or email us with the specifics of your application and we can help you make these decisions and get
you a price quote very quickly.
We can typically can turn around your order in two to three weeks