Patent ID: 6345024
Filing Date: 2002-02-05
Classification: G11B

Abstract:
A reproduction apparatus for selectively playing back a first optical disc wherein two side faces of each of grooves or lands formed thereon are wobbled at a first frequency and address information is recorded on the wobbled grooves or lands in advance and a second optical disc wherein one of two side faces of each of grooves or lands formed thereon is wobbled at a second frequency while the other side face of each of the grooves or lands is formed as a flat face and address information is recorded on the grooves or lands in advance, comprising:an optical head for irradiating light upon a predetermined one of the grooves or lands and those of the lands or grooves adjacent the predetermined groove or land; detection means divided into at least two regions in a tracing direction of said optical head for detecting reflected light from the predetermined groove or land and the adjacent lands or grooves; first calculation means for adding detection outputs of said at least two regions of said detection means; second calculation means for subtracting a first one from a second one of the detection outputs of said at least two regions of said detection means; discrimination means for discriminating whether an optical disc loaded on said reproduction apparatus is the first optical disc or the second optical disc; selection means for switchably selecting one of said first calculation means and said second calculation means; controlling means for controlling said selection means so that, when said discrimination means discriminates that the loaded optical disc is the first optical disc, said first calculation means is selected, but when said discrimination means discriminates that the loaded optical disc is the second optical disc, said second calculation means is selected; and address extraction means for extracting address information based on an output of said first or second calculation means selected by said selection means.