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 cable assembly enables a plurality of cables to be connected to circuitry in a module enclosed in a housing from which flexible strain relief members extend which encase some of the cables. Two of these strain relief members define an area which is generally wedge-shaped and contains a web of flexible material. A generally hourglass-shaped opening in the web releasably receives a loop of another cable which extends into the housing and may be connected to another peripheral device so as to provide strain relief for that other cable. The entire assembly may be a unit molded of elastomeric material which has an opening enclosing a circuit module and forming the strain relief members and the web with its loop retaining strain relief opening. The cable assembly is especially useful in data collection installations for connecting peripheral devices such as bar code scanners and data entry keyboards to a terminal such as a personal computer.

Abstract: In order to control the width of the scanning beam in the scanning direction over a significant range in front of the scanner, an optical assembly including a phase mask is utilized through which the beam passes after being configured into curved wavefronts, as by a lens which provides a focus in the vicinity of the far end of the range. The F/ number of the optical assembly is high and the cone of the beam in the scanning direction is small, for example, less than 5.degree.. The mask is preferably transparent and has a region which may be rectangular, elliptical or circular forming a step through which the center of the beam passes which imposes a phase change with respect to the phase of the wavefronts which do not propagate via the region. The phase change may be uniform or in the form of a weak quadratic phase variation in this region of the mask which changes phase and thus slightly refocuses the beam.

Abstract: A miniature scan engine for scanning a beam of monochromatic (laser) light across a bar code and receiving return light at a detector that provides electrical signals representing the code, utilizes an integral assembly of a laser (laser diode), the detector and a light collector mounted on flexures and rotated so as to scan the beam and receive the return light from the code. The collector is a body of material transmissive at the laser wavelength. The body presents an orientable surface so that the return light is incident at or close to perpendicular to the surface. In the body, parallel to the surface, is a volume hologram grating having Bragg planes arranged in rings around a center region in alignment with the detector. The angles of the Bragg planes vary progressively and decreases in a direction toward the center region so that light incident on the collector at angles of incidence, which vary from perpendicular to the surface by about + or -5.degree.

Abstract: A method and apparatus for measuring the length, width, and height of rectangular solid objects moving on a conveyor. The apparatus includes a light curtain, two laser triangulation range finders, and a pulse tachometer mounted on a frame around a conveyor. As an object is conveyed through the frame, measurements from each of the sensors are correlated by a digital computer to estimate the length, width and height of the object. The method and apparatus does not require a break in the surface of the conveyor, and is insensitive to object placement and orientation on the conveyor.

Abstract: A system for bar code reading and scanning is provided having automatic bar code signal size control. The scanner includes a processor which calculates, in response to a signal power level of the symbol which has been read, a first optical power level when the beam is scanned in a first direction and a second optical power output level when the beam is scanned in a second direction. This calculation is responsive to the power level and the detected signal size of the preceding scan.

Abstract: A system especially suited for powering up and down electronic equipment operated to a power conservation mode, which conserves more power than other power conservation efforts. The system is operated by hitting any key of a keyboard which provides data entry signals via a plurality of data lines. An embodiment disclosed provides a flip-flop having power on and power off outputs and also inputs which change the flip-flop between set and reset states. A first isolation switch connects at least one of the plurality of keyboard data lines to the flip-flop for conditioning the flip-flop into the one of its set and reset states which provides power on output when serial data is provided, as when any key of the keyboard is pressed.

Abstract: A void and spot discrimination apparatus and method for successfully decoding bar code symbols having imperfections therein. A first and a second scan are performed, and a signal return is obtained, in which information is obtained related to a smallest size black bar and white space, as well as a largest size black bar and white space. The signal returns from the first and second scans is sent to a decoder, and third and fourth scans are performed. The signal returns from the third and fourth scans are altered based on the smallest/largest sizes obtained from the two previous scans, in order to eliminate potential ink spreads and print voids. The process is alternated in this manner until a successful bar code decoding is made.

Abstract: A hand held bar code scanning device having a tactile feature in which the hand held device vibrates upon indication of a successful bar code scan. The bar code scanning device includes a scanning circuit, which outputs an acknowledge signal that indicates a successful scan. This acknowledge signal is received by a switch, which closes when the acknowledge signal is in an active state. The input of the switch is connected to a reference potential, and the output of the switch is connected to a vibration motor. When the switch closes, the reference potential is applied to the vibration motor, thereby causing the hand held bar code scanning device to vibrate. This vibration notifies the hand held operator of a successful scan.

Abstract: In order to decode from electrical signals derived by a photodetector which responds to the light returned from the relatively less reflective (black) bars of the code and relatively more reflective (white) bars (also known as spaces), these signals must be digitized into a digital data signal where the black and white bars are represented by opposite logic levels, (for example logic high voltage levels representing the black bars, and logic low voltage levels representing the white bars). The high logic levels are pulses which are separated in time by the low logic levels. A cascade of amplifiers is used to amplify the bar code signal from the photo detector. An amplifier having a logarithmic signal compression characteristic is included in the cascade, preferably after an amplifier which serves to differentiate the signal. The amplified signal is applied to a digitizer including a comparator which is sensitive only to the leading edge.

Abstract: A system for bar code reading and scanning is provided having automatic gain control for accurate reading of bar codes over a range of distance. An amplifier within the system provides a plurality of selectable amplification gain levels for increasing the size of the signal received by a digitizing element. A processor is programmed to select the gain level. The system has a light source, preferably a laser diode, and a laser diode circuit, which provides accurate setting by the processor of the laser optical power output. The laser diode is calibrated according to each selected gain level of the amplifier such that the system can scan within a desired range of distances from the system to a bar code. The system successively scans a bar code, with each scan being at a different amplification level. In the alternative, a signal size detector provides a signal representative of the size of the signal to the digitizer.

Abstract: The system, which is especially suitable for use a a bar code scanner trigger which allows for hands-free scanner operation and non-contact triggering of the scanner by the operator, in one embodiment, comprises a switch and a switch actuator, with the switch mounted proximate to a movable part of the body, and the switch actuator located on the movable part of the body, which part is movable so as to move the switch actuator and switch to within a predetermined proximity of one another and thereby actuate the switch, which will actuate the electronic equipment switched thereby. After the switch has been actuated, moving the part of the body with the switch actuator thereon so as to move the switch actuator and switch beyond a predetermined proximity of one another will deactuate the switch, and thereby deactivate the electronic equipment switched thereby.

Abstract: A D/A converter having a bias circuit that supplies a well-compensated gate voltage to a weighted current source part of the D/A converter, so that any changes in component characteristics due to the manufacturing of the components making up the D/A converter or due to temperature variations in the D/A converter are compensated for to output a correct analog voltage.The bias circuit comprises an amplifier and a p-type FET, where the drain of the p-type FET is fed back to a non-inverting input of the amplifier, and a reference voltage is applied to an inverting input of the amplifier. The bias circuit operates in a negative feedback condition, such that the non-inverting input is kept as close to the reference voltage as possible. A first resistor is connected to the drain of the p-type FET, to determine the current at the drain of the p-type FET. The weighted current source is made up of FETs having similar operating characteristics as the p-type FET of the bias circuit.

Abstract: A bar code scanner includes a separate transmitter and receiver, each being able to ultrasonically transmit and receive data, respectively. The receiver transmits an acknowledgement signal when a protocol is received, and sends the acknowledgement signal to the transmitter which, unless it receives the acknowledgement signal, will retransmit the protocol a predetermined number of times. The transmitter includes a receiver which monitors an ultrasonic frequency band for a time period in which transmission by the transmitter is not allowed. The time period corresponds to a time when another ultrasonic signal in the ultrasonic frequency band is detected by the receiver of the transmitter. Transmission by the transmitter is allowed as soon as the another ultrasonic signal is no longer detected by the receiver of the transmitter.

Abstract: A laser drive and control system which provides protection for a laser diode by preventing excess current from a power source, that normally supplies power to the laser diode, from destroying the laser diode when the voltage supplied by the power source to the laser diode decreases below a certain voltage which causes excess current. The system is implemented in CMOS circuitry for miniaturization into an integrated circuit chip.

Abstract: A hand-held bar code scanner has a removable boot to hold a field-replaceable optical element, which is sandwiched between an opening formed at the nose section of the scanner housing and the face section of the boot. The replaceable optical element can be, for example, a transparent element, filter, lens, or Brewster Window.

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: A bar code hand held scanning terminal which combines a data input device, a display and a scanning engine in a single portable unit. This unit is compact and may be employed in, for example, a scanning terminal which is attached to the back of a hand of an operator. Alternatively, the unit may be employed in a gun-type hand held scanning terminal. The combination has a display which is pivotally connected to the hand held scanning terminal such that the display may be in an open position or in a closed position. A light sensor is used to detect the opening or closing of the display portion of the hand held scanning terminal and maybe used to selectively deactivate the scanning beam when the display is open. The scanning device may be used to read bar code labels for inventory or warehousing, in medical prescription distribution, etc.

Abstract: In order to control the width of the scanning beam in the scanning direction over a significant range in front of the scanner, an optical assembly including a phase mask is utilized through which the beam passes after being configured into curved wavefronts, as by a lens which provides a focus in the vicinity of the far end of the range. The F/ number of the optical assembly is high and the cone of the beam in the scanning direction is small, for example, less than 5.degree.. The mask is preferably transparent and has a region which may be rectangular, elliptical or circular forming a step through which the center of the beam passes which imposes a phase change with respect to the phase of the wavefronts which do not propagate via the region. The phase change may be uniform or in the form of a weak quadratic phase variation in this region of the mask which changes phase and thus slightly refocuses the beam.