Abstract: An apparatus and method for measuring coefficients of retroreflectance of retroreflective surfaces such as road signs involves use of a modified light based range finder. The apparatus includes a power attenuation factor data base which relates pulse width of received pulses to power attenuation of the transmitted pulses. The range finder calculates target range based on time of flight of light pulses. The apparatus automatically calculates the absolute coefficient of retroreflectance for an unknown reflective surface being measured by comparison of the measurement to a reading with the same instrument of a known reflectance standard.

Abstract: A laser beam display includes at least a first and second plurality of laser beam sources, each of which may preferably be an array of semiconductor lasers, providing a plurality of laser beams in an optical path so as to reflect off of reflective facets of a movable reflector and illuminate a display screen. In a color display, each column of the laser array corresponds to a separate primary color. The separate rows of each array correspond to independently activated but simultaneously driven scan lines to be illuminated by the laser beam scanning apparatus. The plural laser beam arrays subdivide the width of the screen into smaller scan segments to increase the scanning angle or increase the horizontal scanning speed of the apparatus. Tilted facets illuminate different vertical sections of the screen with the laser beams as the reflector rotates. A scan format employing simultaneously illuminated diagonal scan tiles provides optimal use of the plural laser beam arrays.

Abstract: Method and device for welding arc ignition of an arc welding apparatus providing a reduced level of high frequency disturbances. A welding electrode and a workpiece are connected with a welding power source and to at least two additional high voltage power sources. A short a periodic high voltage pulse is transmitted from the first high voltage power source to a gap present between the welding electrode and the workpiece, to break down the air present between the welding electrode and the workpiece, and to create a current conducting duct therebetween. The current output of the high voltage power source is restricted in amplitude and rate of rise. The short non-periodic high voltage pulse is superimposed by another, long, high voltage pulse from the second high voltage power source. The long pulse has a current rate of rise not exceeding that of the short pulse, and the open circuit voltage of the second high voltage power source is lower than that of the first high voltage power source.

Abstract: A tilt compensation method, circuit and apparatus utilizes a two axis tilt sensor or two single axis tilt sensors for alerting, a user and/or compensating a surveying instrument for off vertical alignment above a reference point when the instrument support is free to move about the reference point, e.g., when mounted on a monopod support. The sensor comprises a cell having a central electrode and four peripheral electrodes spaced 90 degrees apart around the central electrode. Fluid in the cell chamber changes the conductance of the electrodes with reference to the central electrode. The cell is mounted to the support or to the instrument itself. A microprocessor preferably provides a square wave drive signal selectively to alternate pairs of the opposing electrodes through tristate buffers while at the same time the microprocessor provides a channel select signal to the gate of the tristate buffers to float the idle electrodes.

Abstract: A laser beam mixer combines two or more input laser beams in a coaxial manner to provide an output beam. At least one of the input beams is altered in cross-sectional profile, for example, to an annular cross-sectional shape. Another input beam is placed within the altered beam by a beam combining element having a transmissive portion and a reflective portion to respectively reflect and transmit the two input beams. The beams are combined with minimal beam losses and without diverging a beam profile.

Abstract: A transverse pumping system for a laser rod uses orthogonally arranged banks of laser diodes which create overlapping patterns of illumination inside the rod.

Abstract: A laser rangefinder bow sight adapted for use preferably with a conventional multi-pin bow sight having a frame and a plurality of sighting pins adjustably positioned on said frame. The laser rangefinder has a housing removably fastened to the bow sight frame. The housing supports a laser transmit section, a laser receive section, a precision timing section and a central processing unit (CPU) for measuring distance to a target coupled to an LCD display. The CPU also provides outputs to a plurality of range window indicator lights which are preferably LEDs. The indicator lights may be externally mounted to the bow sight pins or mounted within the rangefinder housing. In the latter case, a plurality of optical fibers are connected to the distance window lights in the housing. Each of the sighting pins is optically coupled to a separate one of the plurality of distance window lights via one of the optical fibers.

Abstract: A closed loop wire saw loop, a method for making the closed wire saw loop, and an apparatus and method for slicing a work piece, in particular, a polysilicon or single crystal silicon ingot, utilizing a closed loop of diamond impregnated wire in which the work piece (or ingot) is rotated about its longitudinal axis as the diamond wire is driven orthogonally to it and advanced from a position adjoining the outer diameter ("OD") of the ingot towards its inner diameter ("ID"). In this manner, the diamond wire cuts through the work piece at a substantially tangential point to the circumference of the cut instead of through up to the entire diameter of the piece and single crystal silicon ingots of 300 mm to 400 mm or more may be sliced into wafers relatively quickly, with minimal `kerf` loss and less extensive follow-on lapping operations. The closed wire saw loop is made by squaring and welding the wire ends together and then twice heat treating the weld at about 1500 F.

Abstract: An apparatus and method for accurately determining a target distance in adverse weather conditions utilizing both LASER and RADAR is disclosed. The radar signals are used to determine an approximate range which is then used as a gating window for the determination of which laser reflection is from the actual target as opposed to a reflection from the atmospheric interference. The method basically comprises the steps of initiating a radar pulse in the direction of a target and receiving a reflection, transmitting a laser signal and receiving a plurality of reflections, determining an approximate range based on the radar signals, and using this approximate range to ascertain which of the laser reflections is from the target. This determination is preferably made by generating a gating signal and gate width from the radar signals and passing the set of laser range signals through the gate to eliminate the false signals and select the signal that survives the gate as the accurate target range.

Abstract: A highly precise range measurement instrument is made possible through the use of a novel and efficient precision timing circuit which makes use of the instrument's internal central processing unit crystal oscillator. A multi-point calibration function includes the determination of a "zero" value and a "cal" value through the addition of a known calibrated pulse width thereby providing the origin and scale for determining distance with the constant linear discharge of capacitor.

Abstract: A sensor for determining the position of a movable object along a selected axis. The system includes a target positioned at a location aligned with the selected axis. An optical energy emitter is mounted on the movable object and has a beam dispersion greater than two degrees directed at the target. An optical energy receiver is mounted on the movable object and aligned to receive optical energy reflected by the target. The optical energy detector generates a receive signal indicating reception of the optical energy. A time of flight circuit coupled to the emitter and receiver generates a flight time signal indicating the elapsed time from emission of the optical energy to reception of reflected optical energy. A control circuit monitors the flight time signal and outputs a position signal indicating position of the movable object with respect to the target.

Abstract: An apparatus and method for measuring coefficients of retroreflectance of retroreflective surfaces such as road signs involves use of a modified light based range finder. The apparatus includes a power attenuation factor data base which relates pulse width of received pulses to power attenuation of the transmitted pulses. The range finder calculates target range based on time of flight of light pulses. The apparatus automatically calculates the absolute coefficient of retroreflectance for an unknown reflective surface being measured by comparison of the measurement to a reading with the same instrument of a known reflectance standard.

Abstract: A circuit and apparatus for generating a light pulse from an inexpensive light-emitting diode (LED) for an accurate distance measurement and ranging instrument comprises an LED and a firing circuit. An optional pre-biasing circuit provides a reverse-bias signal to the LED to ensure the LED does not begin to emit light before a firing circuit can provide a sufficiently high current pulse of short duration as a forward current through the LED. The LED is driven by the firing circuit with a pulse of high peak power and short duration. The resulting light pulse from the LED can be inexpensively used to derive distance and ranging information for use in a distance measurement and ranging device.

Abstract: Disclosed is an optical sensor used for remote laser level monitoring in liquid storage vessels. The sensor is mounted directly to a standard tank nipple, located on top of the vessel, by a threaded connecting means and is linked to a laser measurement device via fiber optic cabling. The level in the vessel is measured as a function of the time required for a laser signal to be transmitted from the sensor, reflected off the liquid surface and returned to the receiver lens located in the sensor.

Abstract: An apparatus and method for slicing a workpiece, in particular, a polysilicon or single crystal silicon ingot, utilizing a diamond impregnated wire saw in which either the workpiece (or ingot) is rotated, either continuously or reciprocally, about its longitudinal axis or the diamond wire saw is rotated, either reciprocally or continuously, about the longitudinal axis of the workpiece as the diamond wire is driven orthogonally to the longitudinal axis of the workpiece. When the relative rotation is continuous, the wire is advanced from a position tangentially adjoining the outer diameter ("OD") of the ingot to a position tangential to its center or inner diameter ("ID"). When the rotation is reciprocating, the wire is advanced from a position tangentially adjoining the outer diameter to a position through the workpiece.

Abstract: A laser catheter for the treatment of lesions and plaque deposits in arteries and other narrow paths having a radiation assembly affixed to a flexible conduit. The conduit generally includes multiple lumens for the passage of an optical fiber, a guide wire, a cooling medium therethrough, or fluid for inflating an angioplasty balloon. The radiation assembly is of short longitudinal profile and includes a generally spherical laser contact member retained within a housing, the latter affixed to the flexible conduit. The radiation assembly provides a dual-mode ablation/melting treatment regime. A longitudinal channel is provided through and along one side of the contact member thereby to permit guide wire positioning of the laser catheter while routing the guide wire away from the laser energy to avoid damage thereto. A balloon, in fluid communication with a catheter lumen, may be positioned rearwardly of the radiation assembly for secondary balloon angioplasty operations.

Abstract: A light beam scanning apparatus employs a movable reflector (32) having a large number of flat reflective sides (44) and a deflector (16) which shifts the light beam (10) at high speed across a plurality of the reflective sides (44). The movement of the reflector (32) is synchronized with the deflection of the light beam (10) to produce a desired scan pattern in a first scan direction (X). The reflective sides (44) of the movable reflector (32) may be angled relative to each other in a second direction (Y) to produce different scan lines thereby providing an X-Y scan pattern. The combined high speed beam deflection and motion of the reflector (32) provide scanning of the beam (10) in parallel scan segments thereby providing high scanning speed of the beam (10) with a high degree of resolution.

Abstract: An apparatus and method for slicing a workpiece, in particular, a polysilicon or single crystal silicon ingot, utilizing a diamond impregnated wire saw in which either the workpiece (or ingot) is rotated about its longitudinal axis or the diamond wire saw is rotated about the longitudinal axis of the workpiece as the diamond wire is driven orthogonally to the longitudinal axis of the workpiece and advanced from a position tangentially adjoining the outer diameter ("OD") of the ingot to a position tangential to its center or inner diameter ("ID"). In this manner, the diamond wire cuts through the workpiece at a substantially tangential point to the circumference of the cut instead of straight through up to the entire diameter of the piece and single crystal silicon ingots of 300 mm to 400 mm or more may be sliced into wafers relatively quickly, with minimal `kerf" loss and less extensive follow-on lapping operations.

Abstract: A laser photo optic breakdown probe and handpiece system especially suited for small-incision cataract removal including an optical fiber through which a pulsed source of laser energy is delivered to a target spaced from the distal end of the fiber. The fiber is routed through a first guide tube with the target mounted at an angle on the end thereof. Holes are provided in the guide tube for the flow of infusion fluid therethrough. A second aspiration tube surrounds and provides rigidity to the guide tube, shields the distal end of the fiber and target, and serves as a channel for aspirated fluids and dislodged cataractous material. The guide tube is affixed to a transfer housing to which infusion and aspiration connections are made. The aspiration tube forms part of a handle assembly which is detachably coupled to the transfer housing.

Abstract: A modular laser-based surveying system is disclosed which comprises a laser-based distance measuring module and a separable compass module removably coupled to the laser based distance measuring module. Each of these modules may be operated as stand alone units as each has its own power supply and display. The system further may comprise a separate angle encoder module adapted to be coupled to either the laser distance measuring module or the compass module and a data logger or computer for processing data transmitted from any or all of the modules.