Tech Briefs

Optical Profilometers Using Adaptive Signal Processing

Sizes would be reduced, leading to development of hand-held profilometers. John F. Kennedy Space Center, Florida A method of adaptive signal processing has been proposed as the basis of a new generation of interferometric optical profilometers for measuring surfaces. Many current optical surface-measuring profilometers utilize white-light-interferometry and, because of optical and mechanical components essential to their operation, are comparable in size to desktop computers. In contrast, the proposed profilometers would be portable, hand-held units. Sizes could be thus reduced because the adaptive-signal-processing method would make it possible to substitute lower-power coherent light sources (e.g., laser diodes) for white light sources and would eliminate the need for most of the optical components of current white-light profilometers. Furthermore, whereas the height scanning ranges of current surface-measuring profilometers are of the order of millimeters, the adaptive-signal-processing method would make it possible to attain scanning ranges of the order of decimeters in the proposed profilometers.

Posted in: Briefs, ptb catchall, Tech Briefs, Photonics

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Optical Surface Analysis Advances Defect Inspection of Optoelectronics

Production defect data leads to better yield management practices. KLA-Tencor Corp., San Jose, California Faced with increasing demand, manufacturers of power devices, microdisplays, and high-brightness light-emitting diodes (HB-LEDs) are focusing on tightening manufacturing process windows to reduce defects. The transparent nature of the substrates used to make many optoelectronic devices such as glass, silicon carbide, and sapphire makes manual defect inspection using optical microscopes an ambiguous and time-consuming process incapable of high-volume production. To meet the need for improved defect inspection, Optical Surface Analyzer (OSA) instruments provide automated defect inspection for optoelectronic device wafers from 2" to 300 mm in diameter.

Posted in: Briefs, ptb catchall, Tech Briefs, Photonics

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Improved Photon-Emission-Microscope System

An advanced photon-emission microscope is combined with the latest image-processing software. NASA’s Jet Propulsion Laboratory, Pasadena, California An improved photon-emission-microscope (PEM) instrumentation system has been developed for use in diagnosing failure conditions in semiconductor devices, including complex integrated circuits. This system is designed primarily to image areas that emit photons, at wavelengths from 400 to 1,100 nm, associated with device failures caused by leakage of electric current through SiO2 and other dielectric materials used in multilayer semiconductor structures. In addition, the system is sensitive enough to image areas that emit photons during normal operation. This system supplants a prior PEM system based on a photon-intensified, gated, charge-coupled-device (CCD) camera.

Posted in: Briefs, ptb catchall, Tech Briefs, Photonics

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Production of Tuber-Inducing Factor

This substance regulates the growth of potatoes and some other plants. A process for making a substance that regulates the growth of potatoes and some other economically important plants has been developed. The process also yields an economically important by-product: potatoes.

Posted in: Briefs, Bio-Medical, Medical

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Vacuum-Assisted, Constant- Force Exercise Device

An important advantage over other exercise machines would be light weight.

Posted in: Briefs, Bio-Medical, Medical

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Modification of a Limbed Robot to Favor Climbing

A kinematically simplified design affords several benefits. The figure shows the LEMUR IIb, which is a modified version of the LEMUR II — the second generation of the Limbed Excursion Mechanical Utility Robot (LEMUR). Except as described below, the LEMUR IIb hardware is mostly the same as that of the LEMUR II. The IIb and II versions differ in their kinematic configurations and characteristics associated with their kinematic configurations. The differences are such that relative to the LEMUR II, the LEMUR IIb is simpler and is better suited to climbing on inclined surfaces.

Posted in: Briefs, TSP, Mechanical Components, Mechanics

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Controlling Herds of Cooperative Robots

A document poses, and suggests a program of research for answering, questions of how to achieve autonomous operation of herds of cooperative robots to be used in exploration and/or colonization of remote planets. In a typical scenario, a flock of mobile sensory robots would be deployed in a previously unexplored region, one of the robots would be designated the leader, and the leader would issue commands to move the robots to different locations or aim sensors at different targets to maximize scientific return. It would be necessary to provide for this hierarchical, cooperative behavior even in the face of such unpredictable factors as terrain obstacles. A potential-fields approach is proposed as a theoretical basis for developing methods of autonomous command and guidance of a herd. A survival-of-the-fittest approach is suggested as a theoretical basis for selection, mutation, and adaptation of a description of (1) the body, joints, sensors, actuators, and control computer of each robot, and (2) the connectivity of each robot with the rest of the herd, such that the herd could be regarded as consisting of a set of artificial creatures that evolve to adapt to a previously unknown environment. A distributed simulation environment has been developed to test the proposed approaches in the Titan environment. One blimp guides three surface sondes via a potential field approach. The results of the simulation demonstrate that the method used for control is feasible, even if significant uncertainty exists in the dynamics and environmental models, and that the control architecture provides the autonomy needed to enable surface science data collection.

Posted in: Briefs, TSP, Mechanical Components, Mechanics

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