The present invention provides a multilevel read-only optical disk and the
method for producing the same. The multilevel read-only optical disk
comprises a plurality of the recording pits, each of the longitudinal
sections of the recording pits has a multilevel arbitrary shape; the
areas of the longitudinal sections of the recording pits are not
identical each other; the area of each of the longitudinal sections of
the recording pits is defined by the following formula: S=.intg.h(x)dx,
where S represents the area of each of the longitudinal sections of the
recording pits, x represents the coordinate value along the width
direction of the recording pits, h(x) represents the pit-depth
distribution function of the longitudinal sections of the recording pits
and the region of the integration covers the whole longitudinal sections
of the recording pits. Furthermore, the run length of the multilevel
read-only optical disk is limited. The present invention obtains the
advantage of both multilevel storage technology and run length limited
(RLL) codes. They can improve prominently the storage capacity and data
transfer rate of read-only optical disk without changing the wavelength
of the laser and optical numerical aperture, and are most compatible with
the conventional read-only optical disk system.