A touch sensor, comprising: - a substrate having a touch surface configured to be touched by a user; - at least one transmitter for exciting acoustic waves in the substrate; - at least one receiver for receiving acoustic waves evoked by the transmitter, characterized in that the touch sensor further comprises: - a plurality of reflecting structures (5, 5a, 5b) arranged across the touch surface for reflecting acoustic waves excited in the substrate; wherein - the reflecting structures (5, 5a, 5b) and the receiver are arranged relative to one another in such a way that an acoustic wave excited in the substrate by the transmitter is reflected at the reflecting structures toward the receiver, and - if the touch surface is touched by a body part of the user or a touching means operated by the user at least a part of the acoustic wave energy excited in the substrate is converted into volume sound waves in the body part or the material of the touching means thereby modifying the acoustic waves propagating in the substrate; and - evaluating means configured for determining the position of a touch on the touch surface using a signal generated by the receiver upon receipt of acoustic waves evoked by the transmitter, and wherein each of the reflecting structures (5, 5a, 5b) is configured to generate a reflected acoustic wave if the touch surface of the substrate is not touched, wherein the evaluating means are configured to detect a touch on a segment of the touch surface between two adjacent reflecting structures (5, 5a, 5b) using the signal generated by the receiver. - a substrate having a touch surface configured to be touched by a user; - at least one transmitter for exciting acoustic waves in the substrate; - at least one receiver for receiving acoustic waves evoked by the transmitter, characterized in that the touch sensor further comprises: - a plurality of reflecting structures (5, 5a, 5b) arranged across the touch surface for reflecting acoustic waves excited in the substrate; wherein - the reflecting structures (5, 5a, 5b) and the receiver are arranged relative to one another in such a way that an acoustic wave excited in the substrate by the transmitter is reflected at the reflecting structures toward the receiver, and - if the touch surface is touched by a body part of the user or a touching means operated by the user at least a part of the acoustic wave energy excited in the substrate is converted into volume sound waves in the body part or the material of the touching means thereby modifying the acoustic waves propagating in the substrate; and - a plurality of reflecting structures (5, 5a, 5b) arranged across the touch surface for reflecting acoustic waves excited in the substrate; wherein - the reflecting structures (5, 5a, 5b) and the receiver are arranged relative to one another in such a way that an acoustic wave excited in the substrate by the transmitter is reflected at the reflecting structures toward the receiver, and - if the touch surface is touched by a body part of the user or a touching means operated by the user at least a part of the acoustic wave energy excited in the substrate is converted into volume sound waves in the body part or the material of the touching means thereby modifying the acoustic waves propagating in the substrate; and - evaluating means configured for determining the position of a touch on the touch surface using a signal generated by the receiver upon receipt of acoustic waves evoked by the transmitter,