| 摘要 |
PURPOSE:To easily multiplex a recording by a multilayer structure and to obtain a memory capacity of twice in density as large as a conventional one by recording colored parts without superposing by beams having different optical energies with first and second photochromatic materials. CONSTITUTION:A beam 11 having an optical energy (hnu1) colors a second photochromatic material 10 to record a colored part 13, and loses the energy to stop in the photochromatic material 10. On the other hand, when a beam 12 having an optical energy (hnu2) (where hnu1>nuh2) capable of coloring a first photochromatic material 9 is radiated, the beam 12 penetrates through the material 10 to color only the material 9, thereby recording a colored part 14. When a beam 15 having an optical energy (hnu1+ hnu2) is radiated, a colored part 16 is recorded on the material 10, and a colored part 17 is recorded on the material 9. |
