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:
Mar. 11, 2008
Filed:
Feb. 16, 2005
Robison J. Bryan, North Hills, CA (US);
Robison J. Bryan, North Hills, CA (US);
Discovision Associates, Long Beach, CA (US);
Abstract
The present invention obtains a more optimal focus in at least two dimensions (such as axial and radial dimensions) by setting or keeping a focus in at least a first dimension (such as both axial and radial dimensions) and detecting and adjusting the focus in a second dimension (such as radial dimension) so that it can be brought to the same focal plane as the focus for the at least first dimension (such as both axial and radial dimension). An actuator lens assembly is used to continually adjust the focus for either primarily the first dimension or primarily the second dimension, using a feedback loop. In one embodiment of the present invention, certain photocell(s), (such as photocells E and F that are normally used for tracking) are compared to certain photocell(s), (such as photocells A and B and C and D) in order to derive a Radial Focus Error (RFE) signal, by observing radial spot size.