Apparatus and method for recording and reproducing optical information

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, the apparatus comprising:

• a pick-up device provided in a face-to-face relationship with the optical information recording medium, the pick-up device comprising:
• a light source;
• an information light generation means for generating information light carrying two dimensional digital pattern information using the beams of light emitted by the light source;
• a recording reference light generation means including modulation means for spatially modulating the beams of light emitted by the light source, for generating reference light for recording being spatially modulated by the modulation means;
• a recording optical system including only one objective lens for projecting the information light generated by the information light generation means and the reference light for recording generated by the recording reference light generation means upon the optical information recording medium, for illuminating the information recording layer on the same side thereof with the information light and the reference light for recording such that the information is recorded 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, the recording optical system projects the information light and the reference light for recording such that a first optical axis of the information light and a second optical axis of the reference light for recording are located on a first same line,
• a reproduction reference light generation means including modulation means for spatially modulating the beams of light in a same manner in which the reference light for recording was modulated when the information was recorded, for generating reference light for reproduction being spatially modulated by the modulation means of the reproduction reference light generation means;
• a reproducing optical system including the objective lens for projecting the reference light for reproduction generated by the reproduction reference light generation means upon the optical information recording medium and for collecting reproduction light generated at the information recording layer when illuminated with the reference light for reproduction, for illuminating the information recording layer with the reference light for reproduction and for collecting the reproduction light on a 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 a third optical axis of the reference light for reproduction and a fourth optical axis of the reproduction light are located on a second same line;
• and
• a detection means for detecting the reproduction light collected by the reproducing optical system.

An optical information recording/reproducing apparatus for recording information in an optical information recording medium having reflecting layer and information recording layer in which information is recorded utilizing holography and for reproducing the information from the optical information recording medium, the apparatus comprising a pick-up device provided in a face-to-face relationship with the optical information recording medium, the pick-up device having:

• a light source,
• an information light generation means for generating information light carrying two dimensional digital pattern information by spatially modulating the beams of light emitted by the light source;
• a recording reference light generation means for generating reference light for recording using the beams of light emitted by the light source;
• a reproduction reference light generation means for generating reference light for reproduction using the beams of light emitted by the light source;
• a recording/reproducing optical system including only one objective lens, for:
• (a) illuminating through the objective lens to the information recording layer with the information light generated by the information light generation means and the reference light for recording generated by the recording reference light generation means such that the information is recorded 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;
• (b) illuminating through the objective lens to the information recording layer with the reference light for reproduction generated by the reproduction reference light generation means;
• and (c) collecting through the objective lens reproduction light generated at the information recording layer when illuminated with the reference light for reproduction on a 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 collected by the recording/reproducing optical system,
• wherein the recording/reproducing optical system projects the information light and the reference light for recording such that a first optical axis of the information light and a second optical axis of the reference light for recording are located on a first same line, and the recording/reproducing optical system projects the reference light for reproduction and collects the reproduction light such that a third optical axis of the reference light for reproduction and a fourth optical axis of the reproduction light are located on a second same line.

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

• a pick-up device provided in a face-to-face relationship with the optical information recording medium, the pick-up device comprising:
• a light source;
• a reproduction reference light generation means including modulation means for spatially modulating the beams of light emitted by the light source in the same manner in which the reference light was modulated when the information was recorded, for generating reference light for reproduction being spatially modulated by the modulation means;
• a reproducing optical system including only one objective lens projecting the reference light for reproduction generated by the reproduction reference light generation means upon the optical information recording medium using the reflecting layer as a reference plane to generate reproduction light and for collecting reproduction light generated at the information recording layer when illuminated with the reference light for reproduction, for illuminating the information recording layer with the reference light for reproduction and for collecting the reproduction light on a same side of the information recording layer that is illuminated with the reference light for reproduction;
• a detection means for detecting the reproduction light collected by the reproducing optical system,
• 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 located on a same line.

An optical information recording apparatus for recording information in a recording medium having reflecting layer and information recording layer in which information is recorded utilizing holography, the apparatus comprising:

• a pick-up device provided in a face-to-face relationship with the recording medium, the pick-up device comprising:
• a light source;
• a servo light source that emits servo light onto the reflecting layer;
• a detection means for detecting reflected servo light that is carrying information of the recording medium, reflected by the reflecting layer such that an optical axis of the servo light and an optical axis of the reflected servo light are located on a same line;
• an information light generation means for generating information light carrying two dimensional digital pattern information using the beams of light emitted by the light source;
• a recording reference light generation means including modulation means for spatially modulating the beams of light emitted by the light source, for generating reference light for recording being spatially modulated by the modulation means;
• and
• a recording optical system including only one objective lens for projecting the information light generated by the information light generation means and the reference light for recording generated by the recording reference light generation means onto the recording medium, for illuminating the information recording layer on the same side thereof with the information light and the reference light for recording such that the information is recorded in the information recording layer in the form of a three dimensional interference pattern as a result of using the reflecting layer as a reference plane to generates interference between the information light and the reference light for recording,
• 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 the reference light for recording are located on a same line.

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, the apparatus comprising:

• a pick-up device provided in a face-to-face relationship with the optical information recording medium, the pick-up device comprising:
• a light source;
• a servo light source that emits first servo light and second servo light onto the reflecting layer;
• a detection means for detecting first reflected servo light which is carrying information of the medium, reflected by the reflecting layer such that an optical axis of the first servo light and an optical axis of the first reflected servo light are located on a same line;
• an information light generation means for generating information light carrying two dimensional digital pattern information using the beams of light emitted by the light source;
• a recording reference light generation means including modulation means for spatially, modulating the beams of light emitted by the light source, for generating reference light for recording being spatially modulated by the modulation means;
• a recording optical system including only one objective lens for projecting the information light generated by the information light generation means and the reference light for recording generated by the recording reference light generation means onto the optical information recording medium, for illuminating the information recording layer on the same side thereof with the information light and the reference light for recording such that the information is recorded in the information recording layer in the form of a three dimensional 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,
• wherein the recording optical system projects the information light and the reference light for recording such that a first optical axis of the information light and a second optical axis of the reference light for recording are located on a first same line;
• a detection means for detecting second reflected servo light that is carrying information of the medium, reflected by the reflecting layer such that an optical axis of the second servo light and an optical axis of the second reflected servo light are located on a same line;
• a reproduction reference light generation means including modulation means for spatially modulating the beams of light in a same manner in which the reference light was modulated when the information was recorded, for generating reference light for reproduction being spatially modulated by the modulation means of the reproduction reference light generation means;
• a reproducing optical system including the objective lens for projecting the reference light for reproduction generated by the reproduction reference light generation means onto the optical information recording medium and for collecting reproduction light generated at the information recording layer when illuminated with the reference light for reproduction, for illuminating the information recording layer with the reference light for reproduction and for collecting the reproduction light on a 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 a third optical axis of the reference light for reproduction and a fourth optical axis of the reproduction light are located on a second same line;
• and
• a detection means for detecting the reproduction light collected by the reproducing optical system.

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

• a pick-up device provided in a face-to-face relationship with the optical information recording medium, the pick-up device having;
• a light source;
• a servo light generation means for generating servo light;
• a detection means for detecting reflected servo light that is carrying information of the medium, reflected by the reflecting layer such that an optical axis of the servo light and an optical axis of the reflected servo light are located on a same line;
• an information light generation means for generating information light carrying two dimensional digital pattern information by spatially modulating the beams of light emitted by the light source, based on the information of the medium;
• a recording reference light generation means for generating reference light for recording using the beams of light emitted by the light source, based on the information of the medium;
• a reproduction reference light generation means for generating reference light for reproduction using the beams of light emitted by the light source, based on the information of the medium;
• a recording/reproducing optical system including only one objective lens, for:
• (a) illuminating through the objective lens to the information recording layer with the information light generated by the information light generation means and the reference light for recording generated by the recording reference light generation means such that the information is recorded in the information recording layer in the form of a three dimensional 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;
• (b) illuminating through the objective lens to the information recording layer with the reference light for reproduction generated by the reproduction reference light generation means;
• and (c) collecting through the objective lens reproduction light generated from the information recording layer when illuminated with the reference light for reproduction on a 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 collected by the recording/reproducing optical system;
• wherein the recording/reproducing optical system projects the information light and the reference light for recording such that a first optical axis of the information light and a second optical axis of the reference light for recording are located on a first same line, and the recording/reproducing optical system projects the reference light for reproduction and collects the reproduction light such that a third optical axis of the reference light for reproduction and a fourth optical axis of the reproduction light are located on a second same line.

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

• a pick-up device provided in a face-to-face relationship with the optical information recording medium, the pick-up device comprising:
• a light source;
• a servo light source that emits servo light onto the reflecting layer;
• a detection means for detecting reflected servo light that is carrying information of the medium, reflected by the reflecting layer such that an optical axis of the servo light and an optical axis of the reflected servo light are located on a same line;
• a reproduction reference light generation means including modulation means for spatially modulating the beams of light emitted by the light source in the same manner in which the reference light was modulated when the information was recorded, for generating reference light for reproduction being spatially modulated by the modulation means;
• a reproducing optical system including only one objective lens for projecting the reference light for reproduction generated by the reproduction reference light generation means onto the optical information recording medium and collecting reproduction light generated from the information recording layer when illuminated with the reference light for reproduction, for illuminating the information recording layer with the reference light for reproduction and for collecting the reproduction light on a same side of the information recording layer that is illuminated with the reference light for reproduction;
• a detection means for detecting the reproduction light collected by the reproducing optical system,
• 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 located on a same line.