The following operators can be used to better focus your queries.
( ) , AND, OR, NOT, W/#
? single char wildcard, not at start
* multi char wildcard, not at start
(Cat? OR feline) AND NOT dog?
Cat? W/5 behavior
(Cat? OR feline) AND traits
Cat AND charact*
This guide provides a more detailed description of the syntax that is supported along with examples.
This search box also supports the look-up of an IP.com Digital Signature (also referred to as Fingerprint); enter the 72-, 48-, or 32-character code to retrieve details of the associated file or submission.
Concept Search - What can I type?
For a concept search, you can enter phrases, sentences, or full paragraphs in English. For example, copy and paste the abstract of a patent application or paragraphs from an article.
Concept search eliminates the need for complex Boolean syntax to inform retrieval. Our Semantic Gist engine uses advanced cognitive semantic analysis to extract the meaning of data. This reduces the chances of missing valuable information, that may result from traditional keyword searching.
Disclosed is a method for obtaining a focus error signal by using differential signals created by the optical spots which are projected to a dual layer detector.
English (United States)
This text was extracted from an ASCII text file.
100% of the total text.
Differential Spotsize Focusing Method by Dual Layer
a method for obtaining a focus error signal by
using differential signals created by the optical spots which are
projected to a dual layer detector.
shows an example of this apparatus. The
beam (1), reflected by an optical disk (2), returns to objective lens
(3). In case the beam was focused on an
optical disk (2), the
returned beam goes to a sensor lens (4) and has a focus point (5),
between the first detector (6) and the second detector (7). The
first detector (6) has a hole which is located in the center of the
beam and is smaller than the beam size.
Detectors (6,7) are adjusted
to the point of equal output in the focal direction of the sensor
lens (4). In this case, objective lens
(4) was located to the
position out of focus. The differential
signal (8) from the
detectors (6,7) is not equal to zero. By
feeding this differential
signal back, the objective lens (3) can be controlled on focus.