# US 9,520,152 B2 · Optical information recording/reproducing apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,520,152 B2 - Document ID: US9520152B2 - Status: Granted - Kind: B2 - Application number: 14/848,683 - Filed: 2015-09-09 - Published: 2016-04-28 - Granted: 2016-12-13 - Earliest claimed: 2014-09-10 - Assignees: Hitachi-LG Data Storage, Inc. - Applicants: Hitachi-LG Data Storage, Inc. - Inventors: Kazuyoshi Yamazaki - Web page: https://patentgrep.com/patent/US9520152B2 ## CPC - G11B 7/1365: Separate or integrated refractive elements, e.g. wave plates - G11B 7/083: {relative to record carriers storing information in the form of optical interference patterns, e.g. holograms} - G11B 7/08564: {using galvanomirrors} - 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) ## Abstract A hologram apparatus and hologram optical system includes: a light source which emits a light beam; a splitter which splits the light beam emitted from the light source into a first light beam and a second light beam; a first lens for exposing an optical information recording medium to convergent light of the first light beam; an optical path angle varying device which causes the second light beam to become incident at substantially the same position as the first light beam in the optical information recording medium and changes an angle of incidence of the second light beam incident on the optical information recording medium; and an optical path shifting element which shifts a position of a light beam incident on the optical information recording medium, according to an angle to the optical information recording medium of the light beam incident on the optical information recording medium. ## Claims ### Claim 1 An optical information recording/reproducing apparatus for recording information on or reproducing information from an optical information recording medium using holography, comprising: a light source which emits a light beam; a splitter which splits the light beam emitted from the light source into a first light beam and a second light beam; a first lens for exposing an optical information recording medium to convergent light of the first light beam; an optical path angle varying device which includes a scanner lens which causes the second light beam to become incident at substantially the same position as the first light beam in the optical information recording medium and an optical path angle varying element which changes an angle of incidence of the second light beam incident on the optical information recording medium; and an optical path shifting element which shifts a position of a light beam incident on the optical information recording medium, according to an angle to the optical information recording medium of the light beam incident on the optical information recording medium. ### Claim 2 (depends on 1) The optical information recording/reproducing apparatus according to claim 1, wherein the optical path shifting element shifts the position of the second light beam incident on the optical information recording medium according to the angle to the optical information recording medium of rays which form the second light beam. ### Claim 3 (depends on 1) The optical information recording/reproducing apparatus according to claim 1, wherein the optical path shifting element shifts the position of rays which form the first light beam according to the angle to the optical information recording medium of the rays which form the first light beam. ### Claim 4 (depends on 1) The optical information recording/reproducing apparatus according to claim 1, wherein the optical path shifting element is made up of a substantially parallel plate. ### Claim 5 (depends on 1) The optical information recording/reproducing apparatus according to claim 1, wherein the scanner lens exposes the optical information recording medium to parallel light of the second light beam. ### Claim 6 (depends on 5) The optical information recording/reproducing apparatus according to claim 5, wherein the optical path shifting element is disposed in the optical path angle varying device. ### Claim 7 (depends on 5) The optical information recording/reproducing apparatus according to claim 5, wherein the optical path angle varying element is such that the size of the second light beam exiting the optical path angle varying element varies according to the angle of the light beam exiting the optical path angle varying element. ### Claim 8 (depends on 1) The optical information recording/reproducing apparatus according to claim 1, wherein the optical path shifting element is fixed during a recording operation of the optical information recording/reproducing apparatus. ### Claim 9 (depends on 6) The optical information recording/reproducing apparatus according to claim 6, wherein the optical path shifting element is disposed in substantially the same posture as the optical information recording medium. ### Claim 10 (depends on 6) The optical information recording/reproducing apparatus according to claim 6, wherein the optical path shifting element has a rotation mechanism that is driven during a recording operation of the optical information recording/reproducing apparatus. ### Claim 11 (depends on 3) The optical information recording/reproducing apparatus according to claim 3, wherein a third lens is disposed in an optical path between the splitter and the first lens, and an optical path shifting element is disposed in the third lens. ### Claim 12 (depends on 2) The optical information recording/reproducing apparatus according to claim 2, wherein the optical path shifting element corrects a refractive misalignment of the second light beam on the optical information recording medium.