DISPLAY DEVICE, DISPLAY METHOD AND OPTICAL DISK CARTRIDGE

摘要

PROBLEM TO BE SOLVED: To provide an optical disk cartridge which does not require processing accuracy of a diffraction grating when a pattern such as characters, figures or the like is to be displayed by diffracted light by a diffraction grating formed in the shell of an optical disk. SOLUTION: The optical disk cartridge has an optical disk (14) having guide grooves for tracking control formed into a spiral or concentric form and a shell (11) having a transmission type diffraction grating (16). The pattern to be displayed is visualized by forming the transmission type diffraction grating (16) corresponding to the pattern in such a manner that when natural light transmitted and diffracted through the transmission type diffraction grating (16) is reflected and diffracted on the optical disk (14) and the reflected light (-first order diffracted light) entering the back face of the transmission type diffraction grating (16) exits perpendicular to the shell 11.