GB864119A - Improvements in or relating to information storage devices - Google Patents

Abstract

864,119. Digital data storage-apparatus. INTERNATIONAL COMPUTERS & TABULATORS Ltd. Feb. 26, 1958 [April 5, 1957], No. 11180/57. Class 106 (1). According to the Specification the remnant polarization of a slab of ferro-electric material can be significantly changed by.subjecting the material simultaneously to an electric field and a mechanical stress, whereas either the electric field or the mechanical stress by itself cause only an insignificant change in polarization. Two embodiments for storing binary data using the principle are described. In the first, Fig. 2, a ferro-electric slab 1 has a mechanical stress wave produced in it by a potential applied to an electrode pair 2, 3 (using the piezo-electric effect). This wave travels along the slab, being absorbed at the ends by two pads 4, and stresses in succession five notional storage cells T1, T2 ... T5, between an electrode pair 2, 5. Thus, in accordance with the above principle, data is entered into a selected cell by applying a potential across the electrode pair 2, 5 at the time when the stress wave reaches the selected cell(s). Further data can be stored in further cells in a similar manner between electrode pairs 2, 6 and 2, 7, and it is suggested that a " one " be entered in every cell between, for example, the 2, 7 electrode pair, so that during read out, which is non-destructive and which is effected merely by sending a stress wave through the slab, the pulses read from the electrode pair 2, 7 can be used as clock pulses. In the second embodiment, Fig. 3, the electric fields applied to selected cells at selected times are produced by two sets of electrodes 13a to 13d and 14a to 14c on a half select basis, and the mechanical stress wave is produced by a coil 11 co-operating with some magneto-strictive material 10.