Apparatus and method for recording and reproducing optical information

An optical information recording method for recording information in an optical information recording medium having reflecting layer and information recording layer in which information recorded utilizing holography in the form of interference pattern as a result of interference between information light carrying two dimensional digital pattern information and reference light for recording having spatial modulation, the method comprising:

• generating the information light carrying the two dimensional digital pattern information;
• spatially modulating the reference light for recording;
• and
• illuminating the information recording layer on a same side thereof with the information light and the reference light for recording located on a same line to record the two dimensional digital pattern information in the information recording layer in the form of an interference pattern as a result of using the reflecting layer as a reference plane to generate interference between the information light and the reference light for recording.

An optical information reproducing apparatus for reproducing two dimensional digital pattern information utilizing holography from an optical recording medium having reflecting layer and an information recording layer in which the information is recorded in the form of interference pattern as a result of interference between information light carrying the two dimensional digital pattern information and reference light for recording having a spatial modulation, the apparatus comprising:

• a reproduction reference light generation means including modulation means for spatially modulating the light for generating reference light for reproduction, the modulation means spatially modulating the reference light for reproduction in the same manner in which the reference light for recording was modulated when the information was recorded;
• a reproducing optical system, for illuminating the information recording layer with the reference light for reproduction on a same side of the information recording layer that is illuminated with the information light and the reference light for recording, using the reflecting layer as a reference plane to generate reproduction light, and for collecting reproduction light carrying the two dimensional digital pattern information on the same side of the information recording layer that is illuminated with the reference light for reproduction;
• and
• a detecting means for detecting the reproduction light carrying the two dimensional digital pattern information collected by the reproduction optical system,
• wherein the reproduction optical system projects the reference light for reproduction onto the reflecting layer and collects the reproduction light such that an optical axis of the reference light for reproduction and an optical axis of the reproduction light are located on a same line.

An optical information reproducing apparatus for reproducing two dimensional digital pattern information utilizing holography from an optical recording medium having reflecting layer and information recording layer in which the information is recorded in the form of interference pattern as a result of interference between information light having a wavelength selected from among a plurality of wavelengths and carrying the two dimensional digital pattern information and reference light for recording having the wavelength selected from among a plurality of wavelengths, the apparatus comprising;

• a wavelength selection means for selecting a wavelength of light illuminating the information recording layer from among a plurality of wavelengths;
• a reproduction reference light generation means for generating reference light for reproduction, having the wavelength selected by the wavelength selection means, said reproduction reference light generation means including modulation means for spatially modulating the reference light for reproduction in the same manner in which the reference light for recording was modulated when the information was recorded;
• a reproducing optical system, for illuminating the information recording layer with the reference light for reproduction on a same side of the information recording layer that is illuminated with the information light and the reference light for recording, using the reflecting layer as a reference plane to generate reproduction light, and for collecting reproduction light on the same side of the information recording layer that is illuminated with the reference light for reproduction;
• and
• a detection means for detecting the reproduction light carrying the two dimensional digital pattern information collected by the reproducing optical system,
• wherein the reproducing optical system projects the reference light for reproduction onto the reflecting layer and collects the reproduction light such that an optical axis of the reference light for reproduction and an optical axis of the reproduction light are located on a same line.

An optical information recording and reproducing apparatus for recording information in and reproduction information from an optical information recording medium having reflecting layer and information recording layer in which information is recorded utilizing holography, the apparatus comprising;

• an information light generator that generates information light by first light based on first information that is carrying first two dimensional digital pattern information;
• a recording reference light generator that modulates second light to generate reference light for recording based on second information that is carrying second two dimensional digital pattern information;
• a recording optical system for illuminating the information recording layer with the information light and the reference light for recording, the information light and the reference light for recording illuminating the information recording layer on a same side such an interference pattern between the information light and the reference light for recording by using the reflecting layer as a reference plane, wherein the recording optical system projects the information light and the reference light for recording such that an optical axis of the information light and an optical axis of reference light for recording are located on a first same line;
• a reproduction reference light generator that modulates light to generate reference light for reproduction based on the second information;
• a reproducing optical system for illuminating the information recording layer with the reference light for reproduction on the same side of the information recording layer that is illuminated with the information light and the reference light for recording and for collecting reproduction light on the same side of the information recording layer that is illuminated with the reference light for reproduction, wherein the reproducing optical system projects the reference light for reproduction and collects the reproduction light such that an optical axis of the reference light for reproduction and an optical axis of the reproduction light are on a second same line.

An optical information recording and reproducing method for recording information in and reproducing information from an optical information recording medium having reflecting layer and information recording layer in which information is recorded utilizing holography in the form of an interference pattern as a result of interference between information light carrying two dimensional digital pattern information and reference light for recording having a spatial modulation, the method comprising:

• generating the information light carrying the two dimensional digital pattern information;
• modulating the light to generate the reference light for recording;
• illuminating the information recording layer with the information light and modulated reference light for recording on a same side of the optical information recording medium such that an optical axis of the information light and an optical axis of the reference light for recording are on a same line;
• recording the information in the information recording layer as a result of using the reflected layer as a reference plane to generate an interference pattern between the information light and the reference light for recording;
• spatially modulating the light to generate reference light for reproduction having a spatial modulation in the same manner in which the reference light for recording was modulated when the information was recorded;
• illuminating the information recording layer with the reference light for reproduction on the same side of the information recording layer that illuminated with the information light and the reference light for recording and collecting reproduction light generated at the information recording layer when illuminated with the reference light for reproduction on the same side of the information recording layer that illuminated with the reference light for reproduction such that an optical axis of the reference light for reproduction and an optical axis of the reproduction light are located on a same line;
• and
• detecting the collected reproduction light.

An optical information reproduction apparatus for reproducing information utilizing holography from an optical information recording medium having reflecting layer and information recording layer in which the information is recorded in the form of interference pattern between information light carrying two dimensional digital pattern information and reference light, the apparatus comprising:

• a reference light generator that spatially modulates the light to generate reference light on the same manner in which the reference light was modulated during recording;
• and
• a reproducing optical system that illuminates, to a same side of the information recording layer that illuminated with the information light and reference light during recording, the information recording layer with the reference light using the reflecting layer as a reference plane to generate reproduction light, and collects reproduction light emanating from the information recording layer,
• wherein the reproduction optical system projects the reference light and collects the reproduction light such that an optical axis of the reference light and an optical axis of the reproduction light are located on a same line.

An optical information recording and reproducing apparatus for recording information in an optical information recording medium having reflecting layer and information recording layer in which information recorded utilizing holography and for reproducing the information from the optical information recording medium, the apparatus including a pick-up device comprising:

• a light source for emitting light;
• an information light generator that spatially modulates a first portion of light that is carrying two dimensional digital information, based on the information;
• a reference light generator including modulation means that generates first reference light for recording and second reference light for reproduction from a second portion of the light, wherein the modulation means spatially modulates the second reference light for reproduction in the same manner in which the first reference light for recording was modulated when the information was recorded;
• and
• an optical system, that illuminates the information recording layer with the information light and the first reference light wherein an optical axis of the information light and an optical axis of the first reference light are on a same line, to record the information in the information recording layer by using the reflecting layer as a reference plane to generates an interference pattern between the information light and the first reference light, and illuminates the information recording layer with the second reference light on the same side of the information recording layer that is illuminated with the information light and the first reference light and collects reproduction light emanating from the information recording layer when illuminated with the second reference light.

An optical information recording and reproducing apparatus for recording information in and reproducing information from an optical information recording medium having reflecting layer and information recording layer in which information is recorded utilizing holography in the form of an interference pattern as a result of interference between information light carrying two dimensional digital pattern information and reference light for recording having a spatially modulation, the apparatus comprising;

• an information light generator unit control to generate plural information light each of which carries corresponding two dimensional digital pattern information;
• a recording reference light generation unit, including a modulator for spatially modulating a light, configured to generate plural reference lights for recording each of which is spatially modulated by said modulator in response to a unique phase modulation pattern for said each two dimensional digital pattern information;
• an optical recording unit configured to illuminate said information recording layer with said plural information lights and said plural reference lights for recording so that an optical axis of each information light and an optical axis of the corresponding reference light for recording are located on a same line, to perform a multiplex recording to record on a same location of said optical information recording medium information in the form of plural interference patterns as a result of using the reflecting layer as a reference plane to generate interferences between said plural information lights and said plural reference lights for recording;
• a reproduction reference light generation unit, including a modulator for spatially modulating the light, configured to generate plural reference lights for reproduction each of which is spatially modulated by said modulator of the reproduction reference light generation unit in response to a unique phase modulation pattern for said each two dimensional digital pattern information in the same manner in which the reference light for recording was modulated when the information was recorded;
• an optical reproducing unit configured to illuminate the information recording layer with the reference light for reproduction generated by the reproduction reference light generation unit on the same side of the information recording layer that is illuminated with the corresponding information light and corresponding reference light for recording and to collect reproduction light generated at the information recording layer when illuminated with the reference light for reproduction on the same side of the information recording layer that is illuminated with the reference light for reproduction;
• and
• a detection unit for detecting the reproduction light collected by the optical reproducing unit.