Patent EA-002247-B1 (EA)
Title: Method and apparatus for forming hologram
IPC: G03H1/30
Filed: 1999-02-26
Abstract: 1. A hologram forming apparatus for forming a hologram for reproducing a three-dimensional image by recording an interference pattern for generating reproduction light associated with a desired three-dimensional image when illuminated with reference light for reproduction in a recording medium in which information is recorded utilizing holography, comprising; a head for illuminating a part of the recording medium with a plurality of beams of recording light for forming a part of the interference pattern to record the part of the interference pattern; position change means for changing the relative positional 15 relationship between the head and the recording medium; and position control means for controlling the positions of the plurality of beams of recording light relative to the recording medium based on return light from the recording medium generated when the recording medium is illuminated with the beams of 20 recording light. 2. A hologram forming apparatus according to claim 1, wherein the recording medium allows recording of a three-dimensional interference pattern and the interference pattern is a three-dimensional interference pattern. 3. A hologram forming apparatus according to claim 1. ^rein at least one of the plurality of beams of recording light is spatially modulated in a modulation pattern calculated based on information of a three-dimensional image. 4. A hologram forming apparatus according to claim 1, wherein the recording medium is formed in a sheet-like 5 configuration and the head illuminates the recording medium with the plurality of beams of recording light on the same side thereof. 5. A hologram forming apparatus according to claim 4, wherein the head radiates the plurality of beams of recording light such that the optical axes of the respective beams of recording light are located on the same line. 6. A hologram forming apparatus according to claim 1, further comprising fixing means for fixing the interference pattern recorded in the recording medium. 7. A hologram forming apparatus according to claim 1, further comprising a guide portion provided under the recording medium having a portion for modulating the return light. 8. A hologram forming apparatus according to claim 1, wherein the position control means performs focus servo and tracking servo. 9. A method for forming a hologram for reproducing a three-dimensional image by recording an interference pattern for generating reproduction light associated with a desired three-dimensional image when illuminated with reference light for reproduction in a recording medium in which information is recorded utilizing holography, comprising the steps of: performing an operation of illuminating a part of the recording medium with a plurality of beams of recording light for forming a part of the -interference pattern to record the part of the interference pattern a plurality of times while changing the relative positional relationship between the recording medium and the beams of recording light  thereby forming a hologram; and controlling the positions of the plurality of beams of recording light relative to the recording medium based on return light from the recording medium generated when the recording medium is illuminated with the beams of recording light. 10. A method for forming a hologram according to claim 9, wherein the recording medium allows recording of a three-dimensional interference pattern and the interference pattern is a three-dimensional interference pattern. 11. A method for forming a hologram according to claim 9, wherein at least one of the plurality of beams of recording light is spatially modulated in a modulation pattern calculated based on information of a three-dimensional image. 12. A method for forming a hologram according to claim 9. wherein the recording medium is formed in a sheet-like configuration and the recording medium is illuminated with the plurality of beams of recording light on the same side thereof. 13. A method for forming a hologram according to claim 12, wherein the plurality of beams of recording light is radiated such that the optical axes of the respective beams of recording light are located on the same line. 14. A method for forming a hologram according to claim 9, further comprising the step of fixing the interference pattern recorded in the recording medium. 15. A method for forming a hologram according to claim 9, wherein the positions of the beams of recording light are controlled based on return light modulated by a guide portion provided under the recording medium having a portion for modulating the return light. 16. A method for forming a hologram according to claim 9, wherein the positions of the beams of recording light are controlled by performing focus servo and tracking servo.