Incandescent illuminating devices are available with a safety coating of silicone rubber to prevent scattering of fragments of the glass envelope upon fracture. However, the coating does not act as an antifragility coating, i.e., such coatings do not provide any significant protection against cracking or breaking of the glass envelope. The silicone rubber acts only as a "safety net" to prevent scattering of pieces of the shattered glass envelope after fracture. Even though the coating provides antiscattering properties, once the envelope is broken the bulb is of no value. Also, because such safety bulbs are generally coated with a silicone rubber on a clear, unetched envelope, the filament of the bulb appears as a bright spot causing an optical glare.
USPTO Backgrounds
USPTO Backgrounds