| 摘要 |
PROBLEM TO BE SOLVED: To ensure the discrimination of the front and rear of a recording medium even when the information recording medium constituted by adhering a first substrate and a second substrate with an adhesive is used in a dark place, by incorporating a luminous material into the adhesive. SOLUTION: The adhesive surface 12a of the first disk substrate 12 and the recording surface 13a of the second disk substrate 13 are bonded by means of the luminous material-contg. adhesive layer 19 consisting of a thermosetting type adhesive, an UV curing type adhesive and a hot melt type adhesive, etc. The luminous material, such as Bi-added CaS crystal powder or cu-added ZnS crystal powder, which is an inorg. fluorescent pigment is disposed into the adhesive. If, for example, the Bi-added CaS crystal powder is dispersed into the adhesive, the adhesive layer 19 emits light to a bluish purple collor in the dark. The emitted light of the adhesive layer 19 is shielded by a function film and is not visible on the front side of the disk 11, i.e., the front surface side of the disk 13 and is checkable only from the rear side of the disk 11, i.e., the front surface of the disk 12. |
