Opto-mechanical adjustment based on sensing label side of optical disc

#Computer users employ writable and rewritable optical discs for a variety of different purposes. They may save programs or data to the discs, for archival or distribution purposes. In the case of CD-type discs, users may make music CD's that can be played in audio CD players, or save music data files to the CD's, such as MP3 files, that can be played in special-purpose CD players. In the case of DVD-type discs, users have greater storage capacity available to them than with CD-type discs, and may be able to make video DVD's that can be played in stand-alone DVD players.

#Many types of optical discs include a data side and a label side. The data side is where the data is written to, whereas the label side allows the user to label the optical disc. Unfortunately, labeling can be an unprofessional, laborious, and/or expensive process. Markers can be used to write on optical discs, but the results are decidedly unprofessional looking. Special pre-cut labels that can be printed on with inkjet or other types of printers can also be used. However, this is a laborious process: the labels must be carefully aligned on the discs, and so on. Special-purpose printers that print directly on the discs can be used, but such printers are fairly expensive.

#In the patent application entitled “Integrated CD/DVD Recording and Label” [attorney docket 10011728-1], filed on Oct. 11, 2001, and assigned Ser. No. 09/976,877, a solution to these difficulties is described, in which a laser is used to label optical discs. However, as a laser ages, it tends to lose its ability to write a given sized mark on the label side of an optical disc at a given level of power applied to the laser. Dust or other opaque or light scattering materials may accumulate on the optical system's lens(es), also affecting its ability to write a mark on the disc's label side at a given level of power.

#FIG. 1 is a diagram of a system according to an embodiment of the invention.

#FIG. 2 is a flowchart of a method according to an embodiment of the invention.

#FIG. 3 is a diagram showing a system in which a central beam of a laser is used for label side sensing of an optical disc, according to an embodiment of the invention.

#In the following detailed description of exemplary embodiments of the invention, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific exemplary embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized, and logical, mechanical, optical, opto-mechanical, and other changes may be made without departing from the spirit or scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims.

#Overview

#FIG. 1 shows an opto-mechanical system 100 according to an embodiment of the invention. The system 100 is used for reading and writing to the label side of an optical disc 102. A laser diode 104 outputs a laser 106 that a diffraction grating 108 separates into a number of laser beams 110. Separation of the laser 106 into the laser beams 110 can be accomplished by using other mechanisms than diffraction with the grating 108, such as with reflection as in a beam splitter, which is amplitude splitting, refraction such as with a beam that is incident upon the vertex of a prism, or scatter. The laser beams 110 pass through a collimator lens 112 to collimate the beams 110, and then through an objective lens 114 to focus the laser beams 110 onto a number of tracks of the label side of the optical disc 102, as indicated by the reference number 115.