| 摘要 |
PURPOSE:To prevent the substrate of a discoid information storage medium from curving by fitting a reinforcing ring made of an annular flat plate so that it is superposed upon the external circumference part of the substrate. CONSTITUTION:On one surface of a discoid substrate 1 made of a transparent plastic plate and having in its center a center hole 1a of rotation where the rotary center shaft 3 of the turntable 2 of an information processor is inserted, an information-formed layer 4 made of a recording layer or light reflective layer annularly is formed. At the external circumference part of each substrate 1, a reinfocing ring 8 made of an annular flat plate for preventing the substrate 1 from curving is fitted while being superposed, thus constituting an information storage medium 9. The reinforcing ring 8 is formed by punching a stainless steel plate having about 1.5mm. thickness, the external diameter of the reinforcing ring 8 is greater than that of the substrate 1, and its external circumference part serves as a guide surface 10. |
