1. Field of the Invention:
This invention relates to an information processing apparatus, and more particularly to an improved apparatus for use in accessing the information recording tracks formed on the medium in a spiral or concentric fashion.
2. Description of the Prior Art:
Conventionally, when an optical disc is used as an information recording medium, precise access must be made from one track to another formed on the optical disc in a radial direction. A two-step access technique that includes coarse access and fine access has been employed.
To achieve the coarse access, an optical head incorporating an objective lens and many other optical parts is moved by a linear motor to a position near the desired track. Thereafter, the objective lens, which is supported movably in a direction crossing the tracks, is moved by a lens actuator so as to achieve fine access.
However, such a two-step access technique requires a complicated structure and takes time to achieve the desired access. Further, erroneous tracking can easily occur due to erroneous detection of the track.