The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 30, 1987
Filed:
Jul. 06, 1984
Majeed Abed, Boulder, CO (US);
Storage Technology Partners II, Louisville, CO (US);
Abstract
Apparatus and methods are disclosed for acquiring and maintaining focus of a coherent light source used to read and write data in an optical disk data storage device. The system uses a conventional astigmatic focus system in conjunction with a signal processor to detect proximity of focus. After proximity of focus is detected, the signal processor enables a fine focus servo system to maintain focus of the coherent light on the disk surface. The system includes a coherent light source for reading and writing data on the optical disk storage medium, a condenser lens for focusing the coherent light on the recording surface of the disk, a cylindrical lens for passing light reflected from the recording surface, a quad light detector responsive to the reflected light from the cylindrical lens for providing an output signal, a controller responsive to the quad detector output signal for providing a control signal when proximity of focus is detected, and a fine servo system for controlling the position of the condenser lens. The system also includes a method of avoiding a false focus on any transparent overcoat layer placed over the recording surface of the optical disk storage medium.