Abstract: A prism beam expander in which the incoming beam is essentially achromatically expanded by 100-500 times in one dimension with transmission through the prism beam expander exceeding 40%. In addition, the input beam is nearly collinear with the output beam. The prism beam expander includes 6 prisms in a preferred system, at least 2 of the apexes of which are oriented on the first side of the optical path while at least 2 of the apexes of the remaining prisms are oriented on the second side of the optical path. The achromatic, high-magnification collinear prism beam expander is used in a tunable laser achieving very narrow linewidths.

Abstract: A two part data gathering system for use in a checkout counter to determine information relating to products to be purchased comprises a scale freely suspended within the checkout counter for determining weights of products, the scale including a scale load receiving plate located below the upper surface of the counter. An optical scanner is supported upon the scale load receiving plate for reading coded labels on the products. The optical scanner has an upper surface including an optical scanning window through which scanning light beams pass and is vertically positioned such that its upper surface is substantially aligned with the upper surface of the checkout counter when the optical scanner is supported upon the scale load receiving plate. The weight of the optical scanner is eliminated from the weight readings provided by the scale and the upper surface of the optical scanner becomes the scale weighing platter for receiving products to be weighed by the scale.

Abstract: A program installed in the microcontroller of an ink jet printer functions as a timer, to keep track of how much time has elapsed since the ink jet cartridge last printed. After a certain amount of time (such as one hour) has elapsed with no printing, the program directs all the nozzles of the cartridge to each print about twenty ink dots. This periodic priming of the nozzles during idle periods prevents viscous ink plugs from building up in and clogging the nozzles.

Abstract: A scanning method and scanning system according to the present invention determines the bar code data printed on a pair of concatenated, two-segment bar code labels, which labels have been scanned by repeatedly sweeping a beam in a succession of scanning passes to determine the left segment data and the right segment data of each of the pair of labels. The labels are of the type in which the left segment data and the right segment data are combinable to form a valid checksum. During scanning, it is noted if a left segment and a right segment were scanned during a single scanning pass across either or both of the pair of labels. Left segment data from a first left segment is combined with right segment data from a first right segment. If a valid first checksum results, the same left data is combined with right segment data from a second right segment. If a valid second checksum results, then left segment data from the second left segment is combined with right segment data from the first right segment.

Abstract: A mounting arrangement vertically mounts a scanner of the type which projects a laser light beam in a scan pattern to find a label on a package and read symbols thereon. The scanner has a housing, a window positioned on a first side of the scanner housing, power and communication cables emerging from a lateral side of the housing, and an optical system within the housing to project the beam through the window. The mounting arrangement includes a support plate for engaging a second side of the scanner housing opposite the first side. The support plate includes means for securing the plate to a horizontal surface. The mounting arrangement further includes a back cover for covering the side of the support plate on the side thereof opposite the scanner. Finally, the mounting arrangement includes a cable cover, securable to the support plate and to the back cover, for covering the cables emerging from the lateral side of the housing.

Abstract: A conveyor system for carrying skids supporting products to be assembled along an assembly line comprises straight sections of driven belt conveyors having skid positioning rails extending above the surface of the belt conveyors on either side with the rails being spaced to receive the skids therebetween to position the skids across the belt conveyors. Arcuate sections of driven roller conveyors are positioned between the straight sections of belt conveyors with the roller conveyors being wider than the belt conveyors to accommodate rotation of the skids as they are carried around the roller conveyors.

Abstract: A pushloop liquid sampling method is an improvement in the method of introducing liquid samples into test equipment (such as for liquid chromotography) via a six port valve. The method involves pulling the sample completely past the sample loop in the six port valve and then pushing the desired amount of sample back into the sample loop.

Abstract: A laser oscillator/amplifier system in which thermally induced birefringence in the gain media of the oscillator is compensated by thermally induced birefringence in the gain media of the amplifier. The system produces a quality output beam efficiently and with high power density in the preferred polarization. The oscillator cavity is characterized by a high reflector at one end and an output coupler at the second end with an oscillator gain medium exhibiting thermally induced birefringence in between. An amplifier exhibiting thermally induced birefringence which matches the thermally induced birefringence in the oscillator gain medium is mounted to receive the output of the oscillator cavity. A ninety degree rotator is mounted between the oscillator gain medium and the amplifier so that compensation for thermally induced birefringence in the oscillator gain medium is compensated by the matching thermally induced birefringence in the amplifier.

Abstract: An optical window is disclosed for association with a scanning face of a laser scanner wherein a laser beam is projected through the window to define a scanning pattern and the optical window is supported such that at least one surface of the window is angularly oriented relative to the scanning face to improve the incidence angles of the laser beam on the window and/or the refractive angles of the laser beam at the window. Preferably, the window comprises a composite block of optical material having sections corresponding to portions of the scanning pattern of the laser scanner and being formed and supported to define the angular orientations of upper and lower surfaces of the sections relative to the scanning face of the scanner in accordance with the corresponding portions of the scanning pattern. Portions of the window through which the laser beam is not transmitted may be used to support the window and preferably are matted to reduce ambient light sensitivity of the laser scanner.

Abstract: Misalignment of a laser beam due to bending of a plasma tube for an internal resonator ion laser, or another structural element supporting beam guiding optics, is controlled by varying the distribution of heat flow out of the plasma tube or structural element to compensate for any misalignment in response to position of the laser beam. A detector is mounted along the optical path of the laser beam, and generates a position signal indicating drift of the laser beam from a preferred position. A cooling system, thermally connected to the structural material of the plasma tube or the structural element and connected to the detector, conducts heat out of the structural material in a controlled distribution in response to the position signal, so that misalignment of the optics due to thermal bending is minimized.

Abstract: A switch cover arrangement for a push-botton electrical switch of the type having a switch actuation button, a switch body on which the button is mounted, and a pair of switch terminals mounted on the switch body protects the switch from its environment and prevents the application of excessive force to the switch actuation button. The switch cover arrangement includes a base plate to which the switch body is secured, and a housing to which the base plate is secured. The housing defines a central cavity for receiving the switch body and the switch button. The central cavity is closed at a first end by the base plate. The switch cover arrangement also includes a button cover mounted for sliding movement in the central cavity toward and away from the base plate. The button cover has a stop portion for contacting the base plate so as to limit sliding movement of the button cover in a direction toward the switch body.

Abstract: The two levels of programming complexity include a high level and an expert level. The command set on the high level includes a plurality of commands which comprise sequences of more detailed commands from the expert level. The expert level commands comprise single actions or operations, or small groups of operations, to be performed by the electromechanical devices, such as valve openings or closures. User access privileges are definable by a system manager to restrict different classes of users to one or more of the levels of complexity.

Abstract: A laser comprising a first mirror having a shape. The shape is generally spherical for typical lasers with the shape of the mirror being defined by the radius of curvature of a reflective surface on the mirror. A second mirror is provided mounted with the first to define a laser cavity. The cross-sectional sizes of the modes of oscillation within the laser cavity are defined by the shape of the first mirror. An aperture at a given location having a fixed cross-sectional size is mounted with the laser cavity. Alternatively, a laser bore which forms an effective aperture at a given location is used. A means is mounted with the first mirror for adjusting the shape of the first mirror so that the cross-sectional size of a selected mode at the given location matches the cross-sectional size of the aperture.

Abstract: A gas valve which is particularly useful in a laser gas fill system requiring repeated fillings includes a conduit positioned between high and low pressure gas regions. Within the conduit is a restriction, and this restriction is closed by a meltable solid material. When the valve is to be opened, heat is applied to the meltable solid material, either internally or externally, causing at least some of the material to flow and allow the passage of gas from the higher pressure region to the lower pressure region. When the pressure between the two regions has substantially equalized, or at least the pressure differential has greatly diminished, surface tension associated with the restriction in the conduit pulls the liquified material back into place to close and reseal the valve, at which point heat application is dicontinued so that the material again becomes solid.

Abstract: A switched resistor regulator is constructed whose duty cycle response is nonlinear with small changes in input control voltage. Specifically, the response of a pulse-width modulator is made to increase less than linearly with small changes in input control voltage. In a preferred embodiment, the pulse-width modulator is altered by comparing the input control voltage with a nonlinear reference signal, rather than the substantially linear reference signal which is used in prior art pulse-width modulators. Specifically, the nonlinear reference signal may be generated by a nonlinear reference voltage circuit, such as an RC charging circuit, or such as a D/A converter controlled by a clocked programmable microprocessor.

Abstract: A PbTe/PbEuSeTe buried heterostructure tunable diode laser and array and the method for making the same. The active region layer is buried between two lead salt semiconductor layers containing europium and selenium that are mutually of opposite conductivity type and have substantially the same lattice constant as the active region layer. In addition, the europium and selenium containing lead chalcogenide layers have an energy band gap greater than the active buried layer and an index of refraction less than the active layer. The buried structure enhances electrical and optical confinement, reduces threshold currents, and provides a stable single mode laser. Strontium, calcium or tin may be used in place of the europium. The buried laser and array are produced using a two-step molecular beam epitary method.

Abstract: A multi-faceted optical device for use in a laser scanner wherein the optical device is rotated about a central axis for rotational movement through a repetitive cycle to reflect and sweep a laser beam through a desired optical space comprises a body member formed by thermoplastic injection molding and shaped to be rotated about a central axis and to define multiple mirror receiving faces. Mirrors are shaped to be received upon the mirror receiving faces of the body member with three raised pads being formed on each of the mirror receiving faces for locating the corresponding mirrors received thereon in a defined orientation relative to the central axis. A fast setting, preferably ultraviolet curable adhesive, is applied to the three pads and the mirrors are forced against the pads and preferably released prior to curing the adhesive by means of the application of ultraviolet light or otherwise to form the optical device.

Abstract: A solid state laser including a block of Nd:YVO.sub.2, Nd:YSAG, or Nd:YAB laser material having a cavity-defining mirror at one of its end surfaces is pumped by a laser diode pumping source having narrow bandwidth and is caused to lase in a single longitudinal mode by controlling the relationship between the pump power, the bandwidth of the lasing transition within the laser material, and the absorption depth of the pump radiation within the laser material.

Abstract: A bar code scanner which preferably generates an asterisk-like scan pattern has a scanner head at the end of a flexible mount enabling operator personnel to orient the scanner head in virtually any position and direction. The scan pattern generator is compact in size, utilizing a laser diode as a source, so that the scan head is easily manipulated to the desired position. In preferred embodiments the scanning mechanism generates the asterisk scan pattern with a rotating mirror or mirrors and a series of peripheral mirrors or lenses, one for each scan line, in an efficient and compact arrangement. The entire asterisk scan pattern may be constantly rotated at a relatively slow rate, so that bar code labels are more likely to be read without deliberate orientation by the operator, particularly in the case of bar codes of high aspect ratio.

Abstract: A point of sale bar code scanner, such as a grocery store check-out label scanner, that is attendant-free and completely automated in providing a listing or a total pricing of a customer's selected items. At each automated check-out, the customer initiates the process, places items on a conveyor, which carries each item separately through a scanner. The scanner reads all sides of each package, including the bottom of the package, since the bar code label could be located on any surface. Serial conveyors are used, and gates preferably control the advancement of items onto a conveyor which will carry the item through the scanning area, such that only one item can be scanned at a time. The conveyor in the scanning area includes a series of belt strips through which an upwardly scanned beam can read the package bottom. Various methods and systems are disclosed for handling "no reads". The customer signifies termination of the process at the appropriate time.