# US 6,298,026 B1 · Magneto-optical head apparatus using evanescent light > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,298,026 B1 - Document ID: US6298026B1 - Status: Granted - Kind: B1 - Application number: 09/401,790 - Filed: 1999-09-22 - Granted: 2001-10-02 - Earliest claimed: 1998-09-24 - Assignees: Sanyo Electric Co., Ltd. - Inventors: Yoshihisa Suzuki; Sayoko Tanaka; Kenichiro Mitani - Web page: https://patentgrep.com/patent/US6298026B1 ## CPC - G11B 7/1365: Separate or integrated refractive elements, e.g. wave plates - B82Y 10/00: Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic - G11B 7/1372: Lenses - G11B 7/1387: using the near-field effect - G11B 11/10534: {for recording by magnetising, demagnetising or transfer of magnetisation, by radiation, e.g. for thermomagnetic recording} - G11B 11/10541: {for reproducing} - G11B 7/0956: {to compensate for tilt, skew, warp or inclination of the disc, i.e. maintain the optical axis at right angles to the disc} - G11B 11/10554: {the transducers being disposed on the same side of the carrier (flying heads G11B11/1058)} - G11B 11/1058: {Flying heads} - 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) - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES ## Abstract A magneto-optical head includes an optical member, objective lens, SIL and coil. The magneto-optical head converts a laser beam to an evanescent light and directs it to a magneto-optical recording medium. Further, the magneto-optical head applies a magnetic field to the magneto-optical recording medium. When tilt is caused, it decreases the tilt angle. The optical member refracts the laser beam to a prescribed direction to be directed to the objective lens when the laser beam is displaced from a designed optical axis. The objective lens allows the laser beam to be focused onto a point on an end face of the SIL. Further, the SIL emits the evanescent light. The optical member is arranged in contact with the optical member. As a result, a signal can accurately be recorded or reproduced even when tilt is caused to an optical disk while alleviating the problem associated with the tilt. ## Claims ### Claim 1 A magneto-optical head recording and/or reproducing a signal to/from a magneto-optical recording medium by a laser beam and a magnetic field, comprising: a first lens having an end face opposite to said magneto-optical recording medium, converting said laser beam to an evanescent light and directing said evanescent light from said end face to said magneto-optical recording medium; a second lens fixed to said first lens for collecting said laser beam at an intersecting point of an optical axis of said first lens and said end face;and an optical member fixed to said second lens for refracting said laser beam toward a direction in which an optical axis of said laser beam comes closer to an optical axis of said second lens in accordance with tilt caused to said magneto-optical recording medium. ### Claim 2 (depends on 1) The magneto-optical head according to claim 1, further comprising a coil wound around said first lens. ### Claim 3 (depends on 1) The magneto-optical head according to claim 1, wherein said first lens is a solid immersion lens. ### Claim 4 (depends on 1) The magneto-optical head according to claim 1, wherein said optical member is in contact with said second lens. ### Claim 5 (depends on 4) The magneto-optical head according to claim 4, wherein said optical member includes a first member provided on said incident side and having a hole at a center, and a second member provided on said emitting side. ### Claim 6 (depends on 5) The magneto-optical head according to claim 5, wherein said second member includes SiN having a refractive index of 1.9 to 2.1. ### Claim 7 (depends on 5) The magneto-optical head according to claim 5, wherein said second member essentially consists of diamond. ### Claim 8 (depends on 5) The magneto-optical head according to claim 5, wherein said second member includes a first sub-member provided on said incident side and having a refractive index of 1.9 to 2.1, and a second sub-member provided on said emitting side and having a refractive index of 2.4 to 2.6. ### Claim 9 (depends on 4) The magneto-optical head according to claim 4, wherein said optical member has a refractive index increasing from an incident side to an emitting side for said laser beam. ### Claim 10 (depends on 9) The magneto-optical head according to claim 9, wherein said optical member includes a first member provided on said incident side and having a first refractive index, a second member provided closer to said emitting side than said first member and having a second refractive index higher than said first refractive index, and a third member provided on said emitting side and having a third refractive index higher than said second refractive index. ### Claim 11 (depends on 10) The magneto-optical head according to claim 10, wherein said first refractive index is 1.45 to 1.55, said second refractive index is 1.9 to 2.1 and said third refractive index is 2.4 to 2.6. ### Claim 12 (depends on 9) The magneto-optical head according to claim 9, wherein said optical member includes a first member provided on said incident side and having a first refractive index, and a second member provided on said emitting side and having a second refractive index higher than said first refractive index. ### Claim 13 (depends on 12) The magneto-optical head according to claim 12, wherein said first refractive index is 1.45 to 1.55 and said second refractive index is 1.9 to 2.1. ### Claim 14 (depends on 12) The magneto-optical head according to claim 12, wherein said first refractive index is 1.45 to 1.55 and said second refractive index is 2.4 to 2.6.