Optical information recording media, method for manufacturing them, and method for recording/reproducing optical information
An optical information recording medium is manufactured by forming a retention recess having a specified depth by one of top and bottom substrates and spacers secured thereto, filling and curing the retention recess with a holographic recording material in the retention recess to form a holographic recording layer having a uniform and appropriate thickness and adhering the other substrate to the holographic recording layer. The optical information recording medium thus manufactured is capable of recording and reproducing information at a high density by the use of holography.
1 . A method for manufacturing an optical information recording medium having a recording layer between a transparent top substrate and a bottom substrates in which optical information is recorded by the use of holography, comprising the steps of:
forming a retention recess having a specified depth defined by either one of said transparent top substrate and said bottom substrate and spacer means secured to said one substrate for receiving a holographic recording material therein;
filling said retention recess with said holographic recording material;
curing said holographic recording material in said retention recess so as thereby to form said holographic recording layer; and
bonding the other of said transparent top substrate and said bottom substrate to said holographic recording layer and said spacer means.
2 . A method for manufacturing an optical information recording medium as defined in claim 1 , wherein said retention recess is filled with said holographic recording material as much as said cured holographic recording layer is flush with said spacer means.
3 . A method for manufacturing an optical information recording medium as defined in claim 1 , wherein said optical information recording medium is in the shape of a disk having a spindle hole and said spacer means comprises an inner annular spacer provided around said spindle hole of said optical information recording medium and an outer annular spacer provided along a periphery of said optical information recording medium.
4 . A method for manufacturing an optical information recording medium as defined in claim 3 , wherein said retention recess is formed by said transparent top substrate and said inner and said outer annular spacer.
5 . A method for manufacturing an optical information recording medium as defined in claim 3 , wherein said retention recess is formed by said bottom substrate and said inner and said outer annular spacer.
6 . A method for manufacturing an optical information recording medium as defined in claim 1 , wherein said holographic recording material is cured by heat.
7 . A method for manufacturing an optical information recording medium as defined in claim 1 , wherein said holographic recording layer is greater than 100 μm in thickness.
8 . An optical information recording medium for recording optical information in holographic recording means by the use of holography, comprising:
a transparent top substrate;
a bottom substrates; and
spacer means secured to either one of said transparent top substrate and said bottom substrate and spacer means for forming a retention recess having a specified depth on said one substrate;
wherein a holographic recording material is filled and cured so as to form a holographic recoding layer and the other of said transparent top substrate and said bottom substrate is secured to said holographic recording layer and said spacer means.
9 . An optical information recording medium as defined in claim 8 , wherein said retention recess is filled with said holographic recording material as much as said cured holographic recording layer is flush with said spacer means.
10 . An optical information recording medium as defined in claim 8 , wherein said optical information recording medium is in the shape of a disk having a spindle hole and said spacer means comprises an inner annular spacer provided around said spindle hole of said optical information recording medium and an outer annular spacer provided along a periphery of said optical information recording medium.
11 . An optical information recording medium as defined in claim 10 , wherein said retention recess is formed by said transparent top substrate and said inner and said outer annular spacer.
12 . An optical information recording medium as defined in claim 11 , wherein said retention recess is formed by said bottom substrate and said inner and said outer annular spacer.
13 . An optical information recording medium as defined in claim 11 , wherein said holographic recording material is cured by heat
14 . A method for manufacturing an optical information recording medium as defined in claim 8 , wherein said holographic recording layer is greater than 600 μm in thickness.
15 . A method for recording information in an optical information recording medium as defined in claim 1 which has a holographic recording layer for information recording by the use of holography, comprising the step of:
irradiating said optical information recording medium coaxially with information-bearing light and reference light so as thereby to generate interference fringes in said holographic recording layer of said optical information recording medium by superposition between said information-bearing light and reference light.
16 . An information recording method as defined in claim 15 , wherein said information-bearing light has intensity distributed in two dimension and said reference light has nearly uniform intensity.
17 . A method for reproducing information from an optical information recording medium as defined in claim 1 in which said information has been recorded in a holographic recording layer by the use of holography, comprising the step of:
irradiating said optical information recording medium with reference light so as to regenerate information bearing-reproduction light from said holographic recording layer.