1376 results about "Optical density" patented technology

Selection criteria for dyes that predicts efficiency and performance for plastics welding. A first stage quantitative calculation screens dyes that possess an absorption band that can be matched to a laser that is suitable for plastic welding. It also identifies absorption troughs in the visible spectrum and establishes relationships between the relative optical densities of the absorption band and trough. A second stage quantitative calculation screens dyes for their contribution to the transparency of the substrate. By combining these two stages, the usefulness of a candidate dye can be quickly, easily and inexpensively determined.

A method for analyzing a blood sample is provided that includes the steps of: a) providing a blood sample having one or more first constituents and one or more second constituents, which second constituents are different from the first constituents; b) depositing the sample into an analysis chamber adapted to quiescently hold the sample for analysis, the chamber defined by a first panel and a second panel, both of which panels are transparent; c) admixing a colorant with the sample, which colorant is operative to cause the first constituents and second constituents to fluoresce upon exposure to predetermined first wavelengths of light, and which colorant is operative to absorb light at one or more predetermined second wavelengths of light; d) illuminating at least a portion of the sample containing the first constituents and the second constituents at the first wavelengths and at the second wavelengths; e) imaging the at least a portion of the sample, including producing image signals indicative of fluorescent emissions from the first constituents and the second constituents and the optical density of the first constituents and the second constituents; f) determining a fluorescence value for each the first constituents and second constituents using the image signals; g) determining an optical density value for each of the first constituents and second constituents, which optical density is a function of the colorant absorbed by the constituents, using the image signals; and h) identifying the first constituents and the second constituents using the determined fluorescence and optical density values.

A method for determining the hematocrit of a blood sample is provided that includes the steps of: 1) depositing the sample into an analysis chamber operable to quiescently hold the sample for analysis, the chamber defined by the interior surfaces of first and second panels and a height extending there between, wherein both panels are transparent, and the height is such that at least some of the red blood cells within the sample contact both interior surfaces of the panels and one or more lacunae within the quiescent sample extend between the interior surfaces; 2) imaging at least a portion of the quiescent sample, which sample portion contains the red blood cells and one or more lacunae to determine an optical density of the imaged portion of the sample on a per image unit basis; 3) selecting and averaging the optical density values of the image units aligned with the red blood cells contacting the interior surfaces, and assigning an upper boundary value of 100% to the average optical density value of those image units; 4) selecting the optical density values of the image units aligned with the one or more lacunae, and assigning a lower boundary value of 0% to the optical density values of those image units; and 5) determining the hematocrit of the sample by assigning relative values to the optical density value of each image of the imaged sample portion as a function of the upper and lower boundary values, and averaging the relative values.

A method and apparatus for determining at least one hemoglobin related parameter of a whole blood sample is provided. The method includes the steps of: a) depositing the sample into an analysis chamber adapted to quiescently hold the sample for analysis, the chamber defined by an interior surface of a first panel, and an interior surface of a second panel, and the chamber has a height extending between the interior surfaces of the panels, wherein the chamber is configured to increase the oxygenation state of the sample to a substantially oxygenated state within a predetermined amount of time after entry into the chamber; b) imaging the at least one red blood cell contacting the interior surfaces, and producing image signals; c) determining an optical density of at least a portion of the imaged red blood cell contacting both interior surfaces; and d) determining the at least one hemoglobin related parameter of the red blood cell contacting the interior surfaces, using the determined optical density and a molar extinction coefficient for oxygenated hemoglobin.

An encoder configuration comprises a dual-modulation scale track pattern that provides a first intensity modulation component for producing periodic signals, and a second intensity modulation component for producing a long-range absolute signal. The dual-modulation scale track pattern increases the range-to-resolution ratio of the encoder without the use of additional scale tracks that would increase the width of the encoder components. The long-range signal may be encoded in the dual-modulation scale track pattern either by varying certain dimensions of pattern elements included in the scale track or by superimposing a layer including an optical density variation along on the track on pattern elements of similar areas. In either case, the net offset and / or amplitude levels of the associated signals are modified along the scale track. These modified offset and / or amplitude levels provide the basis for the long-range absolute signal.

A light is provided having a base unit, an arm extending from the base unit, and a lamp head coupled to the arm. The lamp head includes an LED configured to provide light based on an input drive current, an optical mixing element configured to collect the light produced by the LED and a zoom lens configured to adjust an output size of a spot generated by the light collected in the mixing element. A controller receives DC power from the base unit through the arm. The controller is configured to set the input drive current for the LED to control an output light density of the spot in response to an operator selected input and configured to adjust the output light density of the spot in response to a change in the size of the spot.

An improved illuminator for generating broadband light, and for delivering the light to a sample with an improved delivery efficiency, for higher optical density and / or reduced thermal transfer, than achieved with conventional halogen bulb sources. The illuminator enables spectroscopic analysis in thermally-sensitive or spatially-constrained environments. A phosphor-coated broadband white LED and integrated collimating optics produces a continuous, collimated broadband light beam from 400 nm to 700 nm, which is then transmitted through space to a sample region, such as a living tissue in vivo. A method and system for measuring oxigeneration of mucosal or subsurface tissue is also described.