Other

Hach Company

Stephen K Wilcken

Ernie R Paoli

Richard P Kolman

A turbidimeter is described for measuring the turbidity of a liquid. The turbidimeter includes (a) a sample cell for the liquid to be tested, (b) an optical source such as a light-emitting diode (LED) for producing a light beam directed at the sample cell; (c) an optical detector, and (d) non-imaging optical concentrator located between the sample cell and the optical detector for concentrating light scattered by the liquid in the sample cell. The optical concentrator is preferably integral with the sample cell holder and it exhibits a sharp field of view which minimizes the effect of stray light in the instrument. The optical detector means produces a signal in response to the amount of scattered light it detects. The signal is converted to a turbidity value which is displayed. The turbidimeter can be battery powered and is small and compact.

Turbidimeter with non-imaging optical concentrator

A split-path point-diffraction interferometer (SPPDI) comprising separate signal and reference beam paths is disclosed. A beamsplitter is used to divide a linearly polarized converging incident signal beam into separate signal and reference beam paths prior to focus. The reference beam path comprises a diffracting aperture located at the focal point of the signal beam. The diffracting aperture in the reference beam path produces an expanding, diffraction-limited reference wavefront. The signal and reference beam paths comprise linear polarizers whose yaw, pitch, and roll orientation may be freely adjusted. Yaw and pitch adjustment of one or more linear polarizers provides for adjustment of fringe spacing and orientation. Roll adjustment of one or more linear polarizers provides for adjustment of fringe contrast and intensity. Beam turning mirrors are used to direct the signal and reference beams to a beam combiner. Polarizing analysers are placed in the combined output beams produced by the beam combiner. A double-pass embodiment of an SPPDI comprising a beam splitter and compact laser source is disclosed.

Point-diffraction interferometer utilizing separate reference and signal

A mount for use by optical elements in a laser tooling alignment system. The mount provides a high degree of isolation from external rotational disturbances about any horizontal axis (i.e., pitch and roll) by retaining optical components in a fixed relationship to the local gravity gradient. The mount is a passive gravity referencing two stage, fluid damped pendulum. When a constant deviation optic (e.g. pentaprism beam splitter) is attached to the mount, effective isolation from yaw disturbances is also achieved.

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Grants Pass, OR, United States of America

Stephen K Wilcken