Windshields

 Today, windshields are usually made of two annealed glass panes of the same ordifferent thickness，with inserted thermoplastic layer. Until the 1980's，single panetempered glass windshields were allowed with differential temper between center visibilityarea and close to border. Current solution can grant visibility and permanent glass surface，even in the case of breaking, because the plastic interlayer keeps the broken surfacestogether.On the other hand, in case of a head impact against the windshield during acrash, a tempered glass has a higher strength and, if broken, does not give rise to sharpsplinters as happens with the annealed glass.