# US 5,352,551 A · Process for storing information with high storage density > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,352,551 A - Document ID: US5352551A - Status: Granted - Kind: A - Application number: 08/055,641 - Filed: 1993-04-30 - Granted: 1994-10-04 - Earliest claimed: 1990-12-12 - Assignees: Ciba-Geigy Corporation - Inventors: Jin Mizuguchi; Alain C. Rochat; Gerald Giller - Web page: https://patentgrep.com/patent/US5352551A ## CPC - G11B 7/244: comprising organic materials only - G11B 7/248: porphines; azaporphines, e.g. phthalocyanines - G11B 7/2531: comprising glass - G11B 7/2532: comprising metals - G11B 7/2533: comprising resins - Y10S 430/146: Laser beam - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract A process for storing information in an organic recording layer which, when treated locally with an organic solvent in accordance with the input of information, is able to change its absorption spectrum and/or its photoconductivity such that information can be produced or stored at the treated areas of said layer, wherein the organic solvent is solid at room temperature and is present in the recording layer, or by decomposition of a solid organic precursor which is present in the recording layer, and said solvent is vaporized or melts by the action of laser beams in accordance with the input of information, or said precursor is decomposed by the action of laser beams in accordance with the input of information. The stored information can be read out with a photodetector in the visible or near NIR range or with a built-in electrode system. ## Claims ### Claim 1 A process for storing information in an organic recording layer, which comprises irradiating the organic recording layer with a laser beam, wherein the organic recording layer consists essentially of an organic recording material and a solid organic solvent or a solid organic precursor, and wherein the absorption spectrum and/or photoconductivity of said organic recording material changes in response to a liquid or vaporized organic solvent which is formed by the decomposition, melting and/or vaporization of the solid organic solvent or the solid organic precursor, which decomposition, melting and/or vaporization is effected by the irradiation of the organic recording layer with the laser beam. ### Claim 2 (depends on 1) A process of claim 1 wherein the solid organic solvent or precursor is blended with the recording material to form a uniform recording layer. ### Claim 3 (depends on 1) A process according to claim 1, wherein the recording material is a quinacridone, a dithioquinacridone, a quinacridonequinone, a phthalocyanine, a diketo-, monoketomonothioketo- or dithioketopyrrolopyrrole. ### Claim 4 (depends on 3) A process according to claim 3, wherein the quinacridone or dithioquinacridone is a compound of formula I or II ##STR4## wherein a and b are --H, --F, --Cl, --Br, --CH.sub.3 or --OCH.sub.3, and Z is O or S. ### Claim 5 (depends on 4) A process according to claim 4, wherein a and b are --H and Z is S in formulae I and II. ### Claim 6 (depends on 3) A process according to claim 3, wherein the diketo-, monoketomonothioketo- or dithioketopyrrolopyrrole is a compound of formula IH ##STR5## wherein Z.sub.1 and Z.sub.2 are each independently of the other O or S, and c and d are each independently of the other --H, -Cl, --Br, --CH.sub.3, --OCH.sub.3, --N(CH.sub.3).sub.2, --SC.sub.6 H.sub.5 or --S-alkyl of 1 to 12 carbon atoms. ### Claim 7 (depends on 6) A process according to claim 6, wherein Z.sub.1 and Z.sub.2 are S. ### Claim 8 (depends on 6) A process according to claim 6, wherein Z.sub.1 and Z.sub.2 are S and c and d are --H. ### Claim 9 (depends on 1) A process according to claim 1, wherein the recording layer is applied to a thin light-reflecting metal layer which in turn is applied to a support or a substrate. ### Claim 10 (depends on 1) A process according to claim 1, wherein a transparent support or a substrate is used to which first a transparent conductive layer as electrode is applied, followed by the application of the recording layer and then of a thin conductive metal layer. ### Claim 11 (depends on 1) A process according to claim 1, wherein the organic solvent forms a separate layer within the recording layer. ### Claim 12 (depends on 11) A process according to claim 11, wherein the separate layer is applied to a thin metallic layer which in turn is applied to a support or a substrate, or the separate layer is applied direct to a support or a substrate. ### Claim 13 (depends on 1) A process according to claim 1, wherein the organic solvent is selected from the group consisting of malonic acid, N-phenylurea and, dibenzyl sulfoxide. ### Claim 14 (depends on 1) A process according to claim 1, wherein the change in the absorption spectrum induced by the solvent treatment and the recorded information is read out by a microdetector. ### Claim 15 (depends on 1) A process according to claim 1, wherein the change in photoconductivity induced by the solvent treatment is monitored with a built-in electrode system. ### Claim 16 (depends on 1) An optical recording medium comprising a substrate and a recording layer as claimed in claim 1. ### Claim 17 (depends on 1) A recording material containing electronic information which is obtainable by a process as claimed in claim 1. ### Claim 18 (depends on 1) A process according to claim 1, wherein the organic precursor forms a separate layer within the recording layer.