I would like to know what kind of glass is used in biometric attendance machines over which we press our thumb? Is there something special about these glasses or their manufacturing?
Yes, it is probably the same type of glass used for smartphone screens some version of an aluminium silicate glass that resists scratches, grease, dirt etc for the very same reasons.
They also use oleophobic coatings to avoid sticky fingeprints etc...
According to this glass manufacturer it is more about the optical properties than mechanical ones. They are looking for:
- Homogeneous illumination of the touchsurface
- Transparent and durable in UV and IR light radiation
- Temperature-resistant to heat development in LEDs
They use borosilicate glass and aluminosilicate glass, which are by themselves scratch-resistant.