Optical disc recording-reproducing apparatus in which sector substitution of defective sectors is performed

Claim 1

An optical disc recording-reproducing apparatus for use with an optical disc having a data area, first and second substitution areas respectively containing substitution sectors, and a map sector area containing map sectors, said apparatus comprising: optical head means for recording data in a predetermined sector of a track of said optical disc or for reproducing data recorded in said sector of said track by applying a light beam having a predetermined intensity to said sector, a MODEM circuit for modulating data to be recorded in said sector or for demodulating said data reproduced from said sector, error detecting means for determining whether said sector of said optical disc is a defect sector, said defect sector being a sector of said optical disc found by said error detecting means to have an error based on the data to be recorded in said sector or data reproduced from said sector, and a CPU for performing a substitution operation for substituting a substitution sector from said first substitution area of said optical disc for said defect sector in the event that the number of said defect sectors detected by said error detecting means out of a predetermined number of sectors is less than a given predetermined number, for substituting said substitution sectors of said second substitution area of said optical disc for all the sectors of said predetermined number of sectors including said defect sectors in the event that the number of said defect sectors is greater than or equal to said given predetermined number, and for recording addresses of said defect sectors and said substitution sectors in said map sector area of said optical disc.