Abstract: A print quality, see-through template determines if a hexagonal coded symbol area imprinted on a package falls within allowable limits. The template includes boundaries corresponding to a minimum allowable coded symbol areas and boundaries corresponding to a maximum allowable coded symbol areas. When placed on top of the coded symbol area of the package, it can be determined if the encoded symbol area falls within the bounds shown on the template. The template also includes alignment hexagons for lining up to orientation hexagons that exist on hexagonal code labels. Once these hexagons are lined up, a bull's eye center on the coded symbol area is compared to a dual-size, inverse-color bull's eye on the template, to ensure that the bull's eye meets the specified requirements of the hexagonal code.

Abstract: A hand held bar code scanning device includes scanning circuitry to conduct bar code scanning and a manually actuated optical trigger switch, connected to the scanning circuitry, to initiate bar code scanning.

Abstract: A hand-held bar code scanner has a field-replaceable optical element (250) such as a window using a rubber boot (110) to hold the window (250) proximate to the scanner housing (101) in front of the housing. The optical element is most typically a window but may also be a filter or lens.

Abstract: In order to alleviate condensation which can cause window fogging or frosting conditions when the scanner is used in frigid environments as in refrigerated warehouses, a holder for the scanner is provided which may be located on a forklift or at a strategic location where rapid temperature changes can occur. The holder defines a chamber having doors defined by brushes which contact each other and which are located at one end and across at least a part of the bottom of a housing providing the chamber. The bar code scanner has a head and a handle which may be inserted through the end door into the chamber and supported by a shoulder surface of the bottom of the head around the handle. The doors seal the chamber while having sufficient permeability to allow the escape of moisture. The inside of the chamber may be heated to a temperature which alleviates any fogging.

Abstract: An amplifier circuit provides wide bandwidth low noise performance by minimizing the effect of a pole created by the feedback resistor and the capacitance of the input device, such as a photodiode. This is accomplished by shifting the dominant pole to higher frequencies in the amplifier disclosed. A first amplifier stage receives a signal from an input device, such as the photodiode, and feedback from a second amplifier stage. The first amplifier stage is connected to the second amplifier stage such that a lower gain stage is employed to eliminate the phase shift which occurs if the amplifier alone is used in open loop form. The output of the low gain stage is provided to a second amplifier stage with associated gain setting components such that the dominant pole of the overall amplifier is shifted to a higher frequency, typically two decades higher than available from the single stage open loop amplifier.

Abstract: Random partial scans of a bar code label are utilized to re-create the entire symbol. The symbol is reconstructed by a re-match operation which places partial scanned data into memory and allows the data to be examined so that it is properly loaded whether data is acquired from scanning either the left or right side of the label first. Re-match allows labels having very small aspect ratios at extreme scanning angles to be readily captured.

Abstract: A bar code scanning engine (34) is disposed in a housing (12) with a device (24, 26) which tracks the movement of the housing over a surface (22) displaying symbols such as bar codes and provides an integrated bar code reading and locating assembly, commonly known as a mouse (10). When the mouse is in proximity to the bar code on the surface over which it tracks, switches (18, 19) on the mouse are actuated and circuitry in the mouse associated with the device and with the scanning engine initiates scanning, and provide outputs representing the location of the mouse on the surface and the bar code. The circuitry may be adapted to enable bar code scanning only when the mouse is located at selected positions on the surface where bar codes are expected to be found. The entire mouse assembly may be lifted from the surface and operated in a manner similar to a tethered hand-held bar code scanner using switches (18), (19) and scanner engine (34).

Abstract: A unitary hand-held bar code scanner and reader produces an elliptical beam, oriented with its major axis along the direction of the bars, utilizing optics employing far field diffraction effects to shape the beam and maintain its elliptical aspect (length to width ratio) constant over a distance in front of the scanner were bar codes may be located. The optics eliminates parallax even though the photodetector and light source (preferably a laser diode) are located offset from each other on a board on which the optics are mounted. A housing assembly has channels which mount the board therein without shock absorbing devices. A digital microcomputer controller and peripheral devices regulate the optical power output from the laser diode and prevents catastrophic failure, if the electrical current through the laser diode exceeds safe limits.

Abstract: A miniature scan engine module for bar code reading and data collection systems utilizes a light source and a light collector flexurally supported on a platform which reciprocates on pivots defined by flexures. The light received from the code, as it is scanned, is collected along an optical collector having a surface area approximately equal to the surface area of one side of the scan engine. The optical collector in which the gratings are embedded faces the bar code and pivots with the scanning beam source (a laser diode). A pair of diffraction gratings in a surface of the optical collector which faces away from the code directs the incoming light so that it propagates internally in a substrate within the body of the collector, i.e. in the optic itself to photodetectors via reflective and light concentrating surfaces over the photodetector.

Abstract: In order to prevent a digitizer which receives signals from a bar code reader which scans an inverse code (white bars on black background as opposed to a direct or normal code with black bars on white background) from improperly digitizing a white space as a black bar and also, if desired, to enable the digitizer to operate properly in digitizing signals from direct or inverse codes without switching the digitizer from direct to inverse digitizing mode by operator control, the digitizer is operated, automatically under computer control on different ones of a series of successive scans of the code, which are carried out until the code is successfully read, to provide an output, which is of different states when reading white sections and black sections of the code, and to be restored, respectively, to a state corresponding to the reading of a black section of the code and to a state corresponding to the reading of a white section of the code, when a direct code is to be digitized and when an inverse code is to

Abstract: To enhance the effectiveness of personnel conducting inventory management functions, including data entry of information for products as to their presence, absence, or location, the operator-user is provided with a small and lightweight lapel data entry terminal which can be comfortably worn on a lapel of the operator's clothing, and which can be used to enter data into a remote data center. The lapel data entry terminal provides for acquisition and entry of data derived from verbal pronouncement of code data into a microphone which is coupled to a transmitter through a speech or voice recognition sub-assembly and an analog-to-digital converter sub-assembly. The lapel terminal provides for acquisition and entry of data derived from optical scanning of codes affixed to objects, for example, optical bar code patterns. Such optical codes are read by an optical code reader whose signal output is also coupled to the transmitter.

Abstract: In order to control laser beam propagation, working range and beam cross-section in a bar code scanner, diffractive optics are used to modify the amplitude and/or phase distribution of the beam in the scanner. The beam is diffracted by a mask which has a plurality of apertures in the form of segments which are arranged across the beam cross-section in the vicinity of a converging lens. The segments are sized and their transmission functions selected (one segment having for example 100% transmission and the other 50% transmission) such that bar codes close in and far out from the scanner are in regions of far field diffraction of different segments, or where such regions overlap, thereby extending the working range of the scanner where bar codes of high density can be resolved.

Abstract: A false bar code inhibitor circuit includes a detector, a signal restore circuit, a comparator, a software controller, and a high impedance clamp circuit. Basically, the detector circuit detects the first transition from either high to low reflectivity or low to high reflectivity. The transition triggers the signal restore circuit which is set for a time constant which is longer than the longest possible time needed to encounter another transition during a valid bar code read. Each time a transition is encountered, the signal restore circuit is triggered. The externally adjustable comparator circuit compares the output from the signal restore circuit against a limit, which can be adjusted by the software controller. The output of the comparator drives a clamp which controls when the bar code digitizer can pass an output. With the software controller, the output of the comparator can be controlled allowing for control over the digitizer output.