of the film 12 on the mechanism plate 6 fig4 a it is then possible to observe on the display screen 24 via the camera 15 that the alignment patterns of the electrode are properly placed inside the optical field 2 then the substrate 2 and its glue joint are positioned on the mechanism plate 6 by means of a mobile square a command activates suction of this substrate followed by ccutting of the vacuum under the film 12 3 a command activates rotation of the plate 4 so as to superimpose the two substrates fig4 b 4 with the aid of a motor the table 9 rises so as to bring the first substrate into contact with the second substrate whilst embodying the alignment of the two substrates by means of step motors at x y and in rotation when the two substrates are in contact a command makes the frame 11 bearing the film rise in contact with the plate 4 fig4 c and 4d alignment is then possibly rectified then a command creates suction between the film 12 and the substrates so as to crush the glue joint 3 until the spacers carry out their allotted role fig4 e finally the vacuum under the substrate 2 is cut and the mechanism plate 6 lowers again by about 0 2 mm fig4 f the substrate 2 is then solely.