Marking system using elastic surface waves

A marking system using elastic surface waves comprising:

• a substrate for the surface propagation of linear wavefronts of said waves along a free surface in two separate directions with the vibratory energy propagating perpendicularly to said linear wavefronts, and having an uneven area with a depth significantly less than the wavelength of said elastic surface waves;
• an electro-mechanical transducer coupled to said substrate for producing said waves;
• excitation means connected to said transducer means for supplying pulses to excite said transducer means;
• a stylus having a tip adapted for movement over said surface in contact therewith including a member for feeding a marking substance to said tip to leave a mark on said surface as said tip is moved over said surface and transmitting a pulse induced in said tip by passage of said linear wavefronts of said elastic surface waves;
• and
• chronometric means connected to said excitation means and to said stylus for measuring the time taken by the elastic waves to reach the stylus of said two directions and thus the position of said stylus.