EP0247219A1
Expired / Lapsed
EP
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Direct access storage unit
Assignee: International Business Machines Corp
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Filing: 1986-05-27
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Granted: —
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Expires: 2006-05-27
Abstract
Abstract The storage unit comprises an array of tunnel tips (13) arranged at tunneling distance from a storage medium (2) which is capable of permitting digital information to be written or read through variations of the tunneling current. Each tunnel tip (13) is supported on its own cantilever beam (12) extending across a cavity (14) formed in a common substrate (15). Each cantilever beam (12) as well as the bottom of each cavity (14) are covered with an electrically conducting layer (16, 18) enabling the distance between each one of the tunnel tips (13) and the surface of the storage medium (2) to be electrostatically controlled. The storage medium (2) is attached to the free end of a piezoceramic bender, the end in operation performing a circular motion so that each tunnel tip (13) scans its associated area of the storage medium (2) along a circular track.
Inventors
- 👤 Wolfgang Dieter Pohl
- 👤 Urs Theodor Duerig
- 👤 James Kazimierz Gimzewski
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 15:23
CPC Classifications
G; G11; G11B; G11B21/00; G11B17/00; G11B17/34; G11B19/00; G11B19/20; G11B25/00; G11B25/04; G11B25/043; G11B9/00; G11B9/08; G11B9/12; G11B9/14; G11B9/1418; G11B9/1427; G11B9/1436; G11B9/1463; G11B9/1472; B; B82; B82Y; B82Y10/00; G01; G01Q; G01Q80/00; Y; Y10; Y10S; Y10S977/00; Y10S977/902; Y10S977/932; Y10S977/943; Y10S977/947
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
181 words
Direct access storage unit comprising a storage medium and at least one transducer arranged in juxtaposition with said medium, and means for generating a mutual periodic displacement between said storage medium and said transducer, characterized in that said storage medium (2) is attached to a rigidly anchored two-dimensional positioning device, that said transducer (10, 12) takes the form of a tunneling current detector including a pointed tip (13) facing said storage medium (2) and attached to a cantilever beam (12) whereby the mutual distance between said tip (13) and the surface of the storage medium (2) can be adjusted, and that said means for generating a mutual periodic displacement between the storage medium (2) and said tip (13) include means for periodically energizing the control input of said two-dimensional positioning device (3), the said distance being in the nanometer range, and the reading and/or writing of digital information out of, and into, the storage medium (2) is by means of variation of the tunneling current flowing across the gap between said tip (13) and the surface of said storage medium (2).
Claim 2
Dependent Claim
181 words
Direct access storage unit comprising a storage medium and at least one transducer arranged in juxtaposition with said medium, and means for generating a mutual periodic displacement between said storage medium and said transducer, characterized in that said storage medium (2) is attached to a rigidly anchored two-dimensional positioning device, that said transducer (10, 12) takes the form of a tunneling current detector including a pointed tip (13) facing said storage medium (2) and attached to a cantilever beam (12) whereby the mutual distance between said tip (13) and the surface of the storage medium (2) can be adjusted, and that said means for generating a mutual periodic displacement between the storage medium (2) and said tip (13) include means for periodically energizing the control input of said two-dimensional positioning device (3), the said distance being in the nanometer range, and the reading and/or writing of digital information out of, and into, the storage medium (2) is by means of variation of the tunneling current flowing across the gap between said tip (13) and the surface of said storage medium (2).
Claim 3
Dependent Claim
85 words
Storage unit in accordance with claim 1, characterized in that said transducer (10, 12) is designed as an array (10) of tunnel tips (13) arranged each on a cantilever beam (12) extending from a common substrate (15), that each tunnel tip (13) is associated with a storage area of its own on said storage medium (2), and that the periodic displacement between transducer (10, 12) and storage medium (2) causes each tunnel tip (13) to scan its associated storage area along a closed track (9).
Claim 4
Dependent Claim
40 words
Storage unit in accordance with claim 1, characterized in that said storage medium comprises a silicon substrate (1) and a layer (2) of silicon dioxide arranged on top of said substrate (1) and having a plurality of charge trapping sites.
Claim 5
Dependent Claim
81 words
Storage unit in accordance with claim 1, characterized in that said two-dimensional positioning device comprises a piezoelectric bender element (3) carrying several pairs of electrodes (4, 6; 5, 7) on orthogonal areas of the surface of the bender element (3), and electronic control circuitry for energizing said electrodes (4...7) in such a fashion that the free end of the bender element (3) performs a circular motion so that each tunnel tip (13) scans its associated storage area along a circle (9).
Claim 6
Dependent Claim
38 words
Storage unit in accordance with claim 4, characterized in that the piezoelectric bender element (3) consists of a piezoceramic tube carrying on its cylindrical outer surface four electrodes (4...7) each covering essentially one quarter of the tube's surface.
Claim 7
Dependent Claim
27 words
Storage unit in accordance with claim 4, characterized in that said electronic control circuitry is designed so as to energize said electrodes (4...7) in a repetitive sequence.
Claim 8
Dependent Claim
60 words
Storage unit in accordance with claim 4, characterized in that said electronic control circuitry is designed so as to simultaneously energize alternate pairs of electrodes (4 and 6; 5 and 7) arranged on opposite surface areas of said piezoelectric bender element (3), the two electrodes of each pair (4 and 6, 5 and 7) receiving respectively voltages with opposite polarity.
Claim 9
Dependent Claim
54 words
Storage unit in accordance with claim 4, characterized in that the piezoelectric bender element (3) consists of a piezoceramic tripod with each leg thereof carrying at least one electrode, the electrodes being energizable in such a fashion that the joint of the tripod performs a circular motion, said joint carrying said storage medium (2).
Claim 10
Dependent Claim
90 words
Storage unit in accordance with claim 2, characterized in that each of the cantilever beams (12) is machined from a common substrate (15) and extends across a cavity (14) the bottom of which is at least partly covered with an electrically conductive layer (18), that each cantilever beam (12) also carries an electrically conductive layer (16), said two layers (16, 18) permitting electrostatic deflection of each cantilever beam (12) so as to individually adjust the distance between the associated tunnel tip (13) and the surface of the storage medium (2).
Claim 11
Dependent Claim
55 words
Storage unit in accordance with claim 1, characterized in that said transducer (10, 12) is supported by a holder (21) arranged between a bottom plate (26) and an annular plate (27) by means of a set of springs (22, 23) consisting of a plurality of hard springs (22) and a plurality of soft springs (23).
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