Patent ID: 6069863
Filing Date: 2000-05-30
Classification: G11B

Abstract:
A method of adjusting the positional relationship between a hologram unit and a photo-detector of an optical pickup having a laser device for emitting laser light, a lens for converging the laser light on a disc, a diffraction element divided into two of a first region and a second region to respectively cause diffraction in reflected light from said disc, the photo-detector being separated by a divisional line extending almost in a same direction as a direction of diffraction by said first region and including a first portion and a second portion onto which the reflected light diffracted by said first region converges and a third portion onto which the reflection light diffracted by said second region converges, said adjusting method comprising the steps of:substituting a mirror in a position of said disc;expressing a relationship between a position of said lens and respective output values of said first portion and said second portion as a waveform; anddisplacing said diffraction element to achieve desired characteristics of said waveform.