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:
Dec. 18, 2001
Filed:
Apr. 03, 2000
Allen J. Rushing, Webster, NY (US);
Other;
Abstract
An auto-ranging digital densitometer, for determining the optical density of a test sample, includes a photodetector and a digital logarithmic converter. Within the logarithmic converter, an amplifier circuit is adapted to produce an output signal proportional to intensity of light incident on the photodetector. The amplifier circuit has multiple gains that successively increase, one to the next, by a ratio between 2.3:1 and 5.7:1. Gain select logic selects the gain to provide good density resolution and avoid amplifier saturation. An analog-to-digital converter is adapted to convert the output signal of the amplifier circuit to digital format. A lookup table address is formed at least in part from the output of the analog-to-digital converter. The lookup table outputs at least the lower-order digits of the density value corresponding to the gain and the amplifier output. Density range is extended, resolution improved, and the requirement for a second lookup table is eliminated. The digital logarithmic converter portion of the densitometer is also applicable to other fields besides densitometry.