Busbars! Where would we be without them? They are the hidden, integral heart-and-lungs of every switchable privacy glass panel. This conductive copper strip acts as the conduit for the stepped-down electrical current which energises the liquid crystals within the crucial Polymer-Dispersed Liquid Crystal film. It does this by means of the conductive Indium Tin Oxide coating that has been distributed over the surface of the enclosing PET film.
And how is the Busbar applied? With patience and close attention to detail, that’s how.
Once the PDLC film is cut to size, we trim a narrow strip of its PET film from one side or end. This exposes some of the liquid crystals.
Taking care not to strip the ITO coating underneath, these are removed.
We then apply a fine bead of epoxy sealant along the film edge with a syringe to prevent any delamination.
Next, we apply a coating of silver ink along the strip. When this has dried we apply the copper strip (the Busbar) over that.
To ensure uninterrupted flow of the electrical current when it is applied, we continue this strip around the opposing side of the PET film.
Finally, having adhered the Busbars to both ends of the sheet (most of our Switchglass™ privacy panels are large and require a Busbar at each opposing end of the sheet to permit full and even distribution of the electrical current), it then remains to solder the positive and negative wires to the copper Busbars.
Then we power up the finished sheet and test it before it is laminated between the appropriate, same-sized glass panes.
It’s a painstaking-but-necessary procedure, but ensures our customers are delivered only the best of Switchable Privacy Glass product.