Patent ID: 6510115
Filing Date: 2003-01-21
Classification: G11B

Abstract:
An information recording and reproducing apparatus comprising:a pickup including a first laser emitting light with a wavelength of at least 700 nm, a second laser emitting light with a wavelength of less than 700 nm, an objective lens focusing light emitted by said lasers onto a disk, and an optical detector detecting light reflected off of said disk from said lasers; means for rotating said disk at at least 5 Hz before beaming light from said first laser or said second laser onto said disk; means for driving said laser; and means for discriminating disks for discriminating a type of said disk using an amplitude of said reflected light obtained from said optical detector; wherein: after said rotating means begins rotating said disk at at least 5 Hz, said driving means turns on said first laser to emit light so that power exiting said objective lens is no more than 2 mW; and said discriminating means determines if a first amplitude is greater than a predetermined value, said first amplitude being an amplitude of reflected light obtained by said optical detector when said driving means turns on said first laser to emit light so that power exiting said objective lens is no more than 2 mW; said discriminating means controls said laser driving means so that if said first amplitude is greater than the predetermined value said second laser emits light at no more than 1 mW and if said first amplitude is less than the predetermined value said second laser emits light at at least 0.3 mW, and a second amplitude of reflected light obtained by said optical detector when said second laser is turned on is compared with said first amplitude to perform disk discrimination.