OPTICAL INFORMATION RECORDING MEDIUM COMPRISING A FIRST LAYER HAVING A PHASE THAT IS REVERSIBLY CHANGEABLE AND A SECOND INFORMATION LAYER HAVING A PHASE THAT IS REVERSIBLY CHANGEABLE

摘要

A MULTI-LAYER OPTICAL INFORMATION RECORDING MEDIUM HAS A FIRST INFORMATION LAYER (2) LOCATED AT THE INCIDENT SIDE FOR A LASER BEAM AND ANOTHER INFORMATION LAYER (4) AT THE BACK THEREOF. THUS, IT HAS A LARGE CAPACITY. A RELATIONSHIP THAT RLARLC AND R2AR2C HOLDS FOR THE REFLECTANCES RIA AND RLC OF THE INFORMATION LAYER IN THE IN A RECORDED PORTION AND IN A NON-RECORDED PORTION, AND THE REFLECTANCES R2A AND R2C OF THE INFORMATION LAYER IN A RECORDED PORTION AND IN A NON-RECORDED PORTION. A RELATIONSHIP THAT ALAALC HOLDS BETWEEN THE ABSORPTANCES ALC AND ALA OF THE FIRST INFORMATION LAYER IN THE CRYSTALLINE STATE AND IN THE AMORPHOUS STATE, SIMILARLY, A RELATIONSHIP A2AA2C HOLDS BETWEEN ABSORPTANCES A2C AND A2A OF THE SECOND INFORMATION LAYER IN THE CRYSTALLINE STATE AND IN THE AMORPHOUS STATE. THUS, SIGNALS CAN BE WRITTEN TO THE RECORDING MEDIUM AT A FAST SPEED AND AT HIGH SENSITIVITY. FIGURE 3