Abstract: A method for producing a digital screen printing blank usable in a screen printing process, directly from digital information in the computer, in an economical fashion. In a preferred embodiment, a screen (28) is provided with a photosensitive layer (38), and a digitally determined image from a computer is printed on the screen by means of an inkjet printer. Preferably, a flat bed ink-jet imaging system is used so that the screen can be stretched in a frame and directly placed under the ink-jet head (44). The ink (46) used need not have strong colorant, but functions as a UV mask and thus must contain a UV absorbing pigment. The ink is not absorbed into the photosensitive layer, but remains as an undried image (56) on the surface. The ink must remain wet so that it does not spread and therefore gives a sharp image, and so that the UV absorbent material remains concentrated. The solvent of the ink must be chosen so as to assure that it will not affect the screen.

Abstract: A transducer for a surface acoustic wave (SAW) device comprises a plurality of interdigitized electrode fingers, which change in width along their length. Preferred forms include shapes similar to paired curled brackets { }, paired reversed curled brackets } {, paired rounded brackets ( ) trapezoids, bells, and rhombus <>. Simultaneously, weighting by shape of the interdigitized electrode fingers is determined using of at least one of the following inventive mechanisms: the SAW velocity dispersion effect along the finger's length and the dispersion of the SAW reflection coefficient along the finger's length. Electrode fingers shaped in form of either paired brackets, rhombus, cascaded brackets or cascaded rhombuses are also utilized for SAW beam diffraction control by focussing of the SAW due to the SAW velocity dispersion effect along the fingers' lengths.