Acoustic wave touch panel system.

摘要

A system for recognizing touch positions along a predetermined coordinate axis on a surface of a touch panel display apparatus (10) comprises a substrate having a surface (16) capable of propogating surface acoustic waves and is so characterized that a touch on the surface (16) causes amplitude damping of a surface wave passing through the region of (A1) of touch. An input surface wave tranducer, (T1; T2) coupled to the substrate surface (16) launches a burst of surface waves on the surface (16) in a first direction parallel to the aforesaid axis. An output surface wave transducer (R1; R2) is also coupled to the substrate. A first surface wave reflecting means (G1, G3) derives wave components from the launched wave and reflects them across the display surface (16) to a second wave reflecting means (G2, G4) that redirects the reflected components in a second direction opposite to the aforesaid first direction. The first and second reflecting means (G1-G4) causes wave components to traverse the display surface (16) orthogonally to the coordinate axis along a progression of paths associated with different positions along the coordinate axis. Circuit means coupled to the input (T1; T2) and output transducers (R1, R2) initiate surface wave bursts across the surface (16) as well as detect touch-induced damping of the received waves. The circuit means further includes means for developing an electrical signal representative of the time occurrence of the damping and thus an indication of which of the plurality of paths was traversed by the touch-damped wave and thereby the location (A1) of the touch on the display surface (16).