Abstract: A method and a device for monitoring the transparency of at least a portion of a preassembled laminated pane by analysis of the luminous intensity of the image of a test pattern viewed through the portion of the pane. The luminous intensity, picked up by a detector, of each point of the test pattern viewed through the pane is digitized to produce a number. The numbers obtained for the points of one same image are then averaged, the average obtained being compared with a previously determined theoretical value.

Abstract: The invention concerns the use of a convexing/tempering installation for the manufacture of flat sheet glass or, in general, of glass not bent into convex shape on said installation. It proposes passing glass plates are passed through a conventional convexing/tempering installation, omitting the convexing operation, providing additional heating in the space initially set aside for convexing and/or modifying the tempering conditions initially provided for glass bent into convex shape in said installation. It makes it possible to take advantage of a given convexing/tempering installation for manufacturing tempered flat sheet glass or for heating glass plates with a view to having them bent into convex shape in another installation.