| 摘要 |
PURPOSE:To prevent distortion to a base by providing plural rod projections to the circumference of the base, at least one optical recording part and incorporating the disc circumference part via the projections so as to attain ease of manufacture and improve the mechanical strength. CONSTITUTION:An optical recording disc 1 consists of a couple of optical recording parts 21, 25 having recording layers 41, 45 on disc bases 31, 35 having a hole inserted with a rotary shaft at its center. This bases 31, 35 are discs having a hole inserted with the rotary shaft at the center and made of a resin substantially transparent to write/read light and the bases 31, 35 have plural rod projections 71, 72 at the circumference. The rod projections 71, 72 are prolonged nearly vertically to the recording layer forming face of the bases 31, 35. In incorporating the bases 31, 35 using the projections, the projection 71 has a height nearly equal to the gap length, it is provided to one base 31 and in other case, no projection to the other base 35 is provided and then they are incorporated. |
