Abstract: A signal processing apparatus and method adapted for use in bar code scanners is described. The apparatus forms a derivative signal, and utilizes the derivative signal to detect transition points from white to black bars and vice-versa. Then, the apparatus starts and stops the generation of digital pulses at or about the transition points, thereby generating pulses having widths corresponding to the widths of the bars making up the bar code symbol. The apparatus is capable of successively scanning a bar code symbol more than once, and varying various processing parameters used in forming the derivative signal over the successive scans, including threshold level, overall bandpass, overall amplification, and the like.

Abstract: An optical scanning system including an aiming system which is particularly suitable for handheld scanners where the outgoing light is scanned over a desired angle in a scan plane. The aiming system includes a light source generating an optical beam along an outgoing optical path toward an object to be scanned; a detector for detecting light reflected off the object; an oscillating scan mirror in the outgoing optical path directing light toward the object along a scan plane; and a diffractive optical module positioned in the outgoing optical path adjacent the scan mirror, the diffractive optical module having a pair of diffractive optical elements separated by an aperture, the diffractive optical elements positioned on either side of an aperture along the scan plane, each diffractive optical element de-scanning the portion of the optical beam passing therethrough to form an aiming light beam.

Abstract: An automatic plumb, level, pointing and distance measuring tool uses a visible laser diode to project a beam in any of several different modes through a beam exit window. The tool, approximately the size and shape of a tape measure, can be placed on one edge to project a tilt-compensated vertical beam. Placed on another edge 90.degree.-rotated, the tool projects through the same exit window a tilt-compensated horizontal beam. When laid on either of its larger flat sides, the tilt compensation becomes inoperative and the tool projects a beam which is fixed relative to the housing. Acoustic distance measurement is facilitated using a second component or target side device which receives both a light beam an acoustic signal simultaneously projected from the laser tool across a space to be measured. A receiver in the target side device first detects arrival of a characteristically modulated or pulsed light beam, received at a photodetector on the target side device, and then receives the acoustic signal.

Abstract: A multi-layer graded reflectivity mirror (GRM) with high effective reflectivity is suitable for use in large aperture laser systems with relatively low gain. The GRMs are manufactured with multiple dielectric layers with a thickness profile that eliminates the interference fringes, while providing a reflectivity which tapers smoothly from a peak to zero. The mirror is formed on a substrate having a first surface and a second surface opposite the first. The substrate consists of a material which has low absorption at a given wavelength .lambda.. A first dielectric layer is formed on the first surface of the substrate which has an index of refraction n.sub.1 and having an optical thickness profile with a maximum optical thickness of .lambda./4 at a center which essentially continuously decreases away from the center to a minimum optical thickness of Z at a perimeter P. A second dielectric layer is formed on the first dielectric layer having an index of refraction n.sub.

Abstract: A thin film coating deposited on a substrate, the substrate having a first surface and a second surface opposite the first surface. The coating comprises a first dielectric layer, on the first surface of the substrate, having an index of refraction n.sub.1 and having an optical thickness of about d; a second dielectric layer, on the first dielectric layer, having an index of refraction n.sub.2 and having an optical thickness of about d; and a third dielectric layer, on the second dielectric layer, having an index of refraction of n.sub.1 and having an optical thickness of about 2d. The coaing is substantially reflective over at least two regions of wavelengths, each region separated by a region of high transmissiveness. In one aspect, the first dielectric layer is silicon dioxide, the second dielectric layer is titanium dioxide, and the third dielectric layer is silicon dioxide.

Abstract: A pulsed laser system capable of operating at higher repetition rates, while maintaining the efficiency and beam quality of the output pulses comprises first and second gain media with one or more pump energy transducers, such as flashlamps, coupled with each of the gain media. A power supply generates a first sequence of pulses of input power and a second sequence of pulses of input power which drive respective subsets of the pump energy transducers in an independent timing relationship. Thus, two non-aligned 50 Hz sequences of input pulses which are interleaved generate an output pulse stream at 100 Hz from the laser system with the efficiency, beam quality, and average power comparable to that of a 50 Hz laser. By pumping subsets of the pump energy transducers coupled to a laser system in an interleaved fashion, higher repetition rates may be achieved with better output beam quality and higher average power than has been obtainable with prior art systems.

Abstract: A high efficiency pumping scheme mode matches the TEMOO laser mode volume with a plurality of linearly spaced laser diode pumping sources positioned along a lateral side of a block of laser material. The cavity resonator within the block is configured in a tightly folded zig-zag configuration. Pump radiation from the diode pumping sources is collimated by an optical fiber and the fold angle is selected to mode match the pump radiation to the mode volume.A laser oscillator is followed by one or more cascaded amplifier stages including a block of laser material arranged in a tightly folded zig-zag configuration. Pump radiation from the diode pumping sources is collimated by an optical fiber and the fold angle is selected to mode match the pump radiation to the mode volume.

Abstract: An automated retail point of sale scanning system includes a means for preferentially aligning an item traveling on an item path and through a scanning region such that two or more surfaces to be scanned are stably maintained in a substantially coplanar alignment with a corresponding focal plane of a bar code scanner. Two orthogonally disposed belts define an item path. The belts are tilted at an angle from the horizontal so that an item placed on either belt will have at least two surfaces stably registered by gravity, one surface to each adjacent belt. Alternatively, a stationary platen is disposed orthogonally to a transport belt such that at least two surfaces of the item being scanned are stabilized in a focal plane coplanar with a bar code scanner, one surface of the item being stabilized against the platen and another surface being stabilized against the adjacent transport belt.

Abstract: An assembly for use in a laser instrument which produces a plane of laser light by reflection from a cone. The assembly includes a weak focusing lens which improves the control over the planarity of the plane of light produced. Because it is weak, the weak focusing lens can be positioned over a relatively large distance to produce slight changes in the focus of the beam which is reflected to produce the plane of light. Critical, time consuming, and expensive manufacturing requirements can be relaxed, while improved performance results in superior laser instruments.

Abstract: A rotatable, bakeable vacuum sealed mount for an optical element, suitable for use on an endbell assembly for a gas discharge tube or as an integral part of a gas discharge tube for an ion laser comprises an elongated support member, having an axis and a passage along the axis of the support member. A first end of the support member is connected by a vacuum tight seal to the vacuum sealed chamber of the gas discharge tube, so that the passage has an opening toward the vacuum sealed chamber. A second end of the support member is connectable by vacuum tight seal to the optic, so that the second end of the passage has an opening toward the optic. A portion of the support member has a yield strength allowing adjustment by twisting of the support member about the axis for establishing a rotational alignment of the optic without breaking the vacuum of the vacuum sealed chamber.

Abstract: A system for scanning bar code labels and for providing data related thereto includes scanning means for optically scanning bar code labels and providing an electrical, binary scan signal in response thereto. The scanning means includes a scanner and a scanner controller, and an integrated circuit. The integrated circuit includes a converter means, responsive to the scanning means, for translating the electrical, binary scan signal into a related sequence of digital words. The integrated circuit further includes a microprocessor means, responsive to the converter means, for translating the related sequence of digital words into data. The microprocessor means has first and second microprocessor circuits for independently translating the sequence of digital words into data. The microprocessor means also has a random access memory for storing the appropriate software to control operation of the first and second microprocessor circuits.

Abstract: A syringe of relatively simple construction which is capable of both accurate and reproducible sample volume withdrawals, including volumes of 1.0 .mu.l or less, is provided. The syringe drive mechanism is preferably adapted for use in a liquid sampling apparatus and includes a threaded lead screw, a drive for rotating the screw, and a syringe having a plunger for withdrawing a liquid sample. The plunger is mechanically connected to the rotating lead screw by a nut threaded onto the screw and a slider mechanism associated with the nut which also is secured to the plunger. The nut is designed so that lateral misalignment of the drive screw does not affect the precise linear movement of the slider mechanism, and consequently, the plunger. This provides a mechanism which is less expensive to assemble and align properly, but which has a high degree of accuracy and reproducibility.

Abstract: A point of sale system involving a series of check stands with POS cash registers and bar code scanners includes a lottery ticket issuing and redemption system. A number pick stand in the store, apart from the checkout stands, enables the customer to choose numbers. Pick slips can be generated by the customer at this stand, and bear a bar coded transaction number which can be communicated to a lottery device at each check stand. The pick slip is readable at the check stand bar code reader along with a series of store-inventory items. The customer is automatically charged for the lottery ticket, and the ticket is printed at the check stand. At the time the ticket is issued, the lottery transaction is recorded via modem to the central lottery computer of the state or other controlling agency. In another embodiment the number pick stand may encode the actual picked numbers on the pick slip, in an extended field bar code.

Abstract: A handheld scanner including a housing with a top head portion and a bottom handle portion with a contoured hand rest portion therebetween. A scanner trigger is located on the top of the top head portion which can be actuated either by a thumb or finger. The angular scanner structure, the trigger location, and the transparent scanning window enables the user to intuitively aim the scanner where the user's finger is aimed. The trigger centerline mark to aid in aiming the scanner at bar codes. A "V"-shaped aiming mark on top of the scanner head also aids in aiming the scanner. The angular shape of the scanner allows it to rest comfortably in the user's hand when being held, or alternately permit it to lie securely on a table without rocking when not being held yet still allow it to be easily picked up by the user.

Abstract: A bar code scanner housing assembly for enclosing the components of a bar code scanner is provided. The bar code scanner housing assembly comprises a cartridge including an upper window which is removably mounted therein and a housing including a recess for receiving the cartridge, a lower window mounted within the recess and means for generating bar code scan lines. The cartridge is removably mounted within the recess such that the surface of the cartridge is substantially flush with the upper surface of the housing. The housing assembly may include a mask molded into the recess so as to minimize the amount of ambient light passing into the housing. The housing assembly may also comprise a groove surrounding the lower window which has a removable gasket disposed therein for sealing the space between the upper window and lower window. The housing assembly may comprise a window cartridge which eliminates the need for a separate upper window disposed within the cartridge of a bar code scanner housing assembly.

Abstract: A method and apparatus for automatically controlling the depth of earth grading for utilization with a grader or paver is disclosed. The method includes determination of time taken for an acoustic pulse to travel from a transducer to a reference surface and back, with this value being used to calibrate a microprocessor-controlled distance-measuring device. As the grader moves over a surface to be graded, the distance to the reference surface is constantly detected by a repeated emission and detection of such acoustic pulses. The timing of the echoed pulses is converted to addresses in a look-up table which contains control words symbolizing commands to be given to hydraulic rams carried by the grader. By implementing these commands, the depth of the blade relative to the reference surface is constantly updated, compensating for variations with the height of the reference surface. A thermistor is provided to automatically compensate for temperature variations as the grading takes place.

Abstract: A method and apparatus for mounting a compact optical scanner utilizes a one or two-piece mounting bracket to secure the scanner. A bevelled surface on the inside of the bracket cooperated with a conversely bevelled surface on the scanner to prevent removal of the scanner through the top surface of the bracket. Flexible extensions support the scanner and flex out of the way to allow insertion and removal of the scanner.

Abstract: A scanner including an oval-shaped handle and a round dome-shaped scanner head with a transparent scanning window above the trigger area of the dome. Markings on top of the scanner to aid with aiming, and a multi-color indicator light on top of the dome.

Abstract: A laser alignment apparatus is provided for use in positioning workpieces relative to one another and first and second spaced-apart substantially parallel reference planes. The laser alignment apparatus comprises a first projector for providing first and second reference beams of light disposed in a substantially orthogonal relationship with respect to one another. A second projector provides third and fourth reference beams of light disposed in a substantially orthogonal relationship with respect to one another. The first and second projectors are positioned relative to one another so that the first and third reference beams of light are substantially collinear with one another and the second and fourth reference beams of light are positioned substantially parallel to one another.

Abstract: A focus compensating lens structure wherein a lens means for collimating laser light produced by a source has an index of refraction which varies with temperature and wavelength to compensate for temperature effects on the wavelength of light produced by the laser source and the length of the mounting on which the source and lens are disposed.