Abstract: The operating depth of field for a bar code scanner, preferably a laser scanner, is increased by placing a cubic phase mask (CPM) in the scanning beam. The masked beam is then scanned and reflected off a bar code and received by a photodetector. The received signal is then processed to recover the original unperturbed representation of the bar code pattern. The processed signal has an increased depth of field over an unmasked scanner signal.

Abstract: An imaging module in one embodiment includes at least one multiple color emitting light source comprising a plurality of different colored LED dies each independently driveable so that the overall color emitted by the light source can be controlled and varied. The multiple color emitting light source can be controlled so that the color emitted by the light source is optimized for imaging or reading in a present application environment of the module. Further, the module can be configured so that control of the multiple color emitting light source automatically varies depending on a sensed condition, such a color present in a field of view of the module, the distance of the module to a target, and/or a predetermined criteria being met so that feedback is provided to a user. The module in a further aspect can include illumination light sources and aiming light sources which project light in different wavelength emission bands.

Abstract: An imaging module in one embodiment is adapted so that a position of a lens assembly can be finely adjusted relative to a position of an image sensor. A retainer and lens assembly according to the invention are complimentary configured so that the lens assembly is slidably received in the retainer. The retainer include in one embodiment two apertures defined in sidewalls thereof. The first aperture accommodates a fixture pin for use in finely adjusting the position of the lens assembly within the retainer. The second aperture accommodates an adhesive material for adhesively bonding the lens assembly to the retainer. Adhesive material may further be applied in the first aperture.

Abstract: An imaging module in one embodiment includes a printed circuit board, an image sensor electrically connected to the printed circuit board, a support assembly for supporting at least one optical element, and an illumination system for generating an illumination pattern onto a target. The illumination system may include illumination light sources and diffusers for diffusing light from the illumination light sources. The module may further include an aiming system having an aiming light source, an aperture for stopping light from the aiming light source, and an optical element for projecting an aiming pattern into target area. Either or both of the illumination and aiming systems may include light redirecting elements such as mirrors or prisms.

Abstract: An imaging module in one embodiment includes an aiming system having a light source, an aperture and an optical element positioned optically forward of the aperture wherein the aiming system projects a crisp and sharp aiming pattern onto a target over a wide range of distances. In one embodiment, an aiming system is configured so that a lens operates as an aperture to project a crisp sharp aiming pattern over a wide range of distances including distances at which the aiming pattern is less than optimally focused. In another embodiment an aiming system is configured so that light emanating from a thin aperture is imaged in such manner that a crisp, sharp aiming pattern is defined over a wide range of distances. The aiming pattern in one embodiment includes sharply defined lateral edges which are useful in sighting target indicia.

Abstract: The present invention is an imaging module including various optical components and a circuit board, which, in one embodiment, carries essentially an entirety of illumination and aiming LEDs of the module. The module includes a combination of features which result in the size of the module being reduced. The module may comprise a refractive optic diffuser plate manufactured using a textured surface mold.

Abstract: An optical assembly for use with optoelectronic readers. An imaging optical assembly having an imaging optical axis forms an image of a two-dimensional region on an optoelectronic imaging device. An aiming pattern generator including at least a point-like aiming light source and an interferometric pattern generating optical element project onto the two-dimensional region a luminous aiming pattern that approximately coincides with the field of view of the imaging device. The aiming optical axis of the aiming pattern remains approximately coincident with the field of view of the imaging device over the range of reader-to-target distances over which the reader is used.

Abstract: A bar code reader is provided which can read bar code symbols of varying contrast, from high to medium to low contrast. The bar code reader includes a digitizing circuit which digitizes an analog signal representing the reflectance function of a scanned bar code by comparing the analog signal to a threshold signal. In the present invention, the threshold signal is switchable between a first state wherein the threshold signal is a standard threshold signal suitable for digitizing analog signals representing medium to high contrast bar code symbols and a second state wherein the threshold signal is a non-standard threshold signal suitable for digitizing analog signals representing low contrast bar code symbols. In one embodiment of the invention, the threshold signal is manually adjustable.

Abstract: A hand-held optical reader for reading 2D bar code symbols. The reader includes an illuminating system for illuminating the symbol and an optical system for focusing an image thereof on a 2D image sensor. The image sensor is of the type which allows its imaging parameters, such as exposure, to be controlled by external circuitry. The reader also includes an image sensor processor which sets and changes the imaging parameters used by the image sensor as necessary to meet predetermined image quality criteria and to reduce the time necessary to complete a read operation.

Abstract: A low profile optical unit for use in a 2D bar code reader. A vertically disposed light redirecting panel having contoured reflective openings therein is mounted in the front of the unit and an LED behind the panel. Light emitting diodes for illuminating a target are mounted on the LED board behind the contour openings whereby direct light and reflected light illuminates a target. An imager housing is mounted on the back of the LED board and contains a recess that passes through the back of the housing and a lens barrel that extends forward through holes provided in the LED board and the light redirecting panel. An imager board is secured to the back of the housing which holds a 2D imager that is contained within the housing recess. Circuitry for generating image data signals is mounted on the back of the imager board. A lens holder is threadably mounted in the lens barrel which contains a lens system having a short back focal length for focusing a target image on the imager.

Abstract: An array of reflectors is arranged to approximately match the arrangement of a two-dimensional array of LEDs such as used in a 2-D bar code scanner. Each reflector has at least one reflecting wall for reflecting light from a respective LED, thus increasing the amount of LED light illuminating the target.

Abstract: An apparatus for illuminating an indicia in a sensing region of an object plane. A housing has a median longitudinal vertical plane and a horizontal scanning plane. A reflector for reflecting light directed thereagainst toward the sensing region has a first approximately curvilinear profile in a plane parallel to the scanning plane, and a second approximately curvilinear profile in a plane parallel to the median longitudinal plane. The central portion of the reflector defines an opening whereby light from the sensing may return in generally the same plane as light directed toward the sensing region.

Abstract: There is provided a system of detecting mark-sense indicia wherein the images of a light source and the region of sensitivity of a light sensor are substantially coaxial, coplanar, and coextensive throughout the working depth of field. This system is insensitive to the laminate and the diffusion effects. A light source is aimed at a beam splitter that diverts a portion of the light beam through optics that focus the light on a reflective target containing a bar code symbol to be scanned. The reflected beam is returned through the optics and the beam splitter, and a portion of the reflected beam is conducted to a light sensor. In this manner, the light path from the detector to the optical sensor is split twice by the beam splitter. The optics are configured so that the light beams that define the field of illumination and the region of sensitivity and which pass between the optics and the target are congruent, having identical optical axes and angles of divergence.

Abstract: There is provided an integrated semiconductor source-detector matrix in which solid state photonic diodes are configured as LEDs, disposed on a substrate and coupled to electronic circuits so that the diodes can be individually driven to emit light or to detect light as may be desired. Providing an integrated matrix of light source (emitter) and light sensor units disposed in close proximity results in each unit having nearly coextensive fields of view and illumination. Apparatus, such as bar code and optical readers utilizing such a matrix are shown, and are insensitive to the diffusion and laminate effects. In alternate embodiments the matrix is coupled to remote sensors or another similar matrix to provide optical communication and interchange devices having high bandwidth.

Abstract: A scanner is provided for reading a target containing indicia, such as bar codes, which includes a means for directing the a light source so that it illuminates a target, a photodetector that generates an electrical signal indicative of the intensity of the detected light, a means for decoding the electrical signal to identify the presence of a target containing a region of relatively high reflectivity, and a means for modifying the level of illumination of the light source either from low to high upon recognition of said region of relatively high reflectivity or from high to low when some predetermined condition, such as the end of the indicia scan, or the passage of a time period without reading indicia, is met.

Abstract: A bar code detection circuit accepts as input the discretized analog output of a CCD array, and performs piecewise linear reconstruction to produces a continuous polylinear output signal. In the region of a bar/space transition, the output signal is a close approximation of the reflectance function of a bar code symbol convolved with the system transfer function of the bar code reader. Linear interpolation is performed in order to determine the offset of a given threshold value from an edge of the CCD analog output.

Abstract: There is disclosed an simplified apparatus that enables optical scanners to achieve minimum field curvature and at the same time provide uniformly distributed light on an image sensor. A single element lens, preferably an aspherical lens made of a plastic material is combined with an aperture stop. The combination is capable of reducing lens aberrations and minimizing image field curvature for an object plane that contains indicia to be scanned or read. A suitably demagnified image of the indicia is focused onto an image sensor such as a CCD array. The spatial light distribution function in the image plane can be equalized by an attenuator, such as a neutral density filter or a slit, suitably configured to compensate for the reduced optical efficiency at large field angles. An aspherical lens containing a dye or a cold mirror can be used for limiting light transmission to a range of wavelengths.

Abstract: A method and apparatus are provided for detecting bar-space and space-bar transitions in a bar code symbol. A sequence of sparsely sampled analog signals from a photodetector in a bar code scanner is representative of the reflectance pattern of a symbol.Following initialization, a threshold, representing the value of the analog signal at a transition point, is derived from observed samples of the bars and spaces in the bar code symbol. Sampled reflectance information is accumulated as the symbol is scanned, and a program driven microprocessor calculates and repeatedly updates this threshold, using observed maxima and minima in the analog samples, and also referencing a binary output to determine whether a bar or space is currently being viewed.When the values of two successive analog samples bracket this threshold, then a bar-space or space-bar transition has occurred. Linear interpolation is performed on the two samples to determine the transition point and an offset from the first of the two samples.