Patent Number: 6,167,022

Title: Optical disc having oscillating land and grooves

Abstract: One or more optical discs, each having a ROM field having information with a length of at least one track formed in convex and concave pit rows, and a rewritable field capable of rewriting the information with a length of at least one track, an information unrecorded field having a length of at least one track located between the ROM field and rewritable field, the rewritable field having a spiral or concentric guide track oscillating in a radial direction, the ROM field having spiral or concentric convex and concave pit rows, and at least a part field at the rewritable field side of the information unrecorded field has a transition field having a spiral or concentric guide track oscillating in the radial direction continuously or intermittently and a track pitch To of the ROM field and a track pitch Tw between grooves and lands of the rewritable field have values such that To>Tw.

Inventors: Ishida; Takashi (Yawata, JP), Tanaka; Shin-ichi (Tuzuki-gun, JP), Mutoh; Akira (Sakai, JP), Takemura; Yoshinari (Settsu, JP), Ohara; Shunji (Higashioska, JP), Satoh; Isao (Neyagawa, JP)

Assignee: Matsushita Electric Industrial Co., Ltd.

International Classification: G11B 27/30 (20060101); G11B 27/19 (20060101); G11B 7/09 (20060101); G11B 7/007 (20060101); G11B 007/00 ()

Expiration Date: 12/26/2017