Bioptical holographic laser scanning system

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Patent issued

08/05/2008

Inventor(s):	Groot, John Good, Timothy Dickson, LeRoy Check, Frank
Assignee	Metrologic Instruments, Inc. (Blackwood, NJ)
Application	No. 11/443,552 filed on 05/30/2006
Current US Class	235/462.01, 235/462.22, 235/462.25, 235/462.36, 235/462.4, 235/462.42, 235/462.43, 235/462.47, 235/472.01, 359/16
Field of search	235/462.4, 235/462.22, 235/462.25, 235/462.36, 235/462.42, 235/462.43, 235/462.47, 235/472.01, 235/462.01, 359/16
International Classes:	G06K 7/10 (20060101)
Examiners
Primary	Michael G. Lee
Secondary	Allyson N Trail
Attorney, agent or firm:	Thomas J. Perkowski, Esq., P.C.
Foreign patents	54-819 (01/01/1979, JP), 51-33710 (03/01/1979, JP), 56-47019 (04/01/1981, JP), 64-48017 (02/01/1989, JP)

A bioptical holographic laser scanning system employing a plurality of laser scanning stations about a holographic scanning disc having scanning facets with high and low elevation angle characteristics, as well as positive, negative and zero skew angle characteristics which strategically cooperate with groups of beam folding mirrors having optimized surface geometry characteristics. The system has an ultra-compact construction, ideally suited for space-constrained retail scanning environments, and generate a 3-D omnidirectional laser scanning pattern between the bottom and side scanning windows during system operation. The laser scanning pattern of the present invention comprises a complex of pairs of quasi-orthogonal laser scanning planes, which include a plurality of substantially-vertical laser scanning planes for reading bar code symbols having bar code elements (i.e. ladder-type bar code symbols) that are oriented substantially horizontal with respect to the bottom scanning window, and a plurality of substantially-horizontal laser scanning planes for reading bar code symbols having bar code elements (i.e. picket-fence type bar code symbols) that are oriented substantially vertical with respect to the bottom scanning window.

What is claimed is:

1. A bioptical laser scanning system providing 360.degree. of omni-directional bar code symbol scanning coverage at a point of sale (POS) station, said bioptical laser scanning system comprising: a horizontal section integrally connected to a vertical section; a horizontal-scanning window formed in said horizontal section; a vertical-scanning window formed in said vertical section, and being substantially orthogonal to said horizontal-scanning window; a first plurality of laser beam folding mirrors disposed within said horizontal section; a second plurality of laser beam folding mirrors disposed within said vertical section; a laser beam generating subsystem for generating a plurality of laser beams; a laser beam scanning subsystem disposed within said horizontal section, for scanning said plurality of laser beams and (i) producing and projecting a first plurality of laser scanning planes through said horizontal-scanning window, and (ii) producing and projecting a second plurality of laser scanning planes through said vertical-scanning window, whereby said first and second pluralities of laser scanning planes (i) intersect within predetermined scan regions contained within a 3-D scanning volume defined between said horizontal-scanning and vertical-scanning windows, and (ii) generate a plurality of groups of intersecting laser scanning planes within said 3-D scanning volume, and wherein said plurality of groups of intersecting laser scanning planes form a complex omni-directional 3-D laser scanning pattern within said 3-D scanning volume capable of scanning a bar code symbol located on a surface of an object presented within said 3-D scanning volume at any orientation and from any direction at said POS station so as to provide 360.degree. of onmi-directional bar code symbol scanning coverage at said POS station.

2. The bioptical laser scanning system of claim 1, wherein a height dimension of the said horizontal section is less than about 4.5 inches for installation of said horizontal section within a countertop surface at said POS.

3. The bioptical laser scanning system of claim 1, wherein said plurality of groups of intersecting laser scanning planes comprises over 60 different laser scanning planes cooperating within said 3-D scanning volume to generate said complex omni-directional 3-D laser scanning pattern.

4. The bioptical laser scanning system of claim 1, wherein each said group of intersecting laser scanning planes comprises (i) a plurality of substantially-vertical laser scanning planes for reading bar code symbols having bar code elements that are oriented substantially parallel with respect to said horizontal-scanning window, and (ii) a plurality of substantially-horizontal laser scanning plane for reading bar code symbols having bar code elements that are oriented substantially orthogonal with respect to said horizontal-scanning window.

5. The bioptical laser scanning system of claim 1, wherein said laser beam scanning subsystem includes a first laser beam production subsystem which comprises a first visible laser diode (VLD), and a second visible laser diode (VLD).

6. The bioptical laser scanning system of claim 1, which further comprises a first light collecting/focusing optical element and a first photodetector to form a first scanning station, and wherein the first light collecting/focusing optical element collects light from predetermined scan regions within said 3-D scanning volume and focuses such collected light onto the first photodetector to produce an electrical signal having an amplitude proportional to the intensity of light focused thereon, and said electrical signal being supplied to analog/digital signal processing circuitry for processing analog and digital scan data signals derived therefrom to perform bar code symbol reading operations.

7. The bioptical laser scanning system of claim 6, which further comprises a second light collecting/focusing optical element and a second photodetector, and wherein the second light collecting/focusing optical element collects light from predetermined scan regions within said 3-D scanning volume and focuses such collected light onto the second photodetector to produce an electrical signal having an amplitude proportional to the intensity of light focused thereon, and said electrical signal being supplied to analog/digital signal processing circuitry for processing analog and digital scan data signals derived therefrom to perform bar code symbol reading operations.

8. The bioptical laser scanning system of claim 7, which further comprises a third light collecting/focusing optical element and a third photodetector, and wherein the third light collecting/focusing optical element collects light from predetermined scan regions within said 3-D scanning volume and focuses such collected light onto the third photodetector to produce an electrical signal having an amplitude proportional to the intensity of light focused thereon, and said electrical signal being supplied to analog/digital signal processing circuitry for processing analog and digital scan data signals derived therefrom to perform bar code symbol reading operations.

9. The bioptical laser scanning system of claim 1, which further comprises a fourth light collecting/focusing optical element and a fourth photodetector, and wherein the fourth light collecting/focusing optical element collects light from predetermined scan regions within said 3-D scanning volume and focuses such collected light onto the fourth photodetector to produce an electrical signal having an amplitude proportional to the intensity of light focused thereon, and said electrical signal being supplied to analog/digital signal processing circuitry for processing analog and digital scan data signals derived therefrom to perform bar code symbol reading operations.

10. The bioptical laser scanning system of claim 1, wherein said laser beam scanning subsystem comprises a holographic scanning disc supporting a plurality of holographic scanning elements.

11. The bioptical laser scanning system of claim 10, wherein wherein said holographic scanning elements are classifiable into a first class of facets having High Elevation (HE) angle characteristics, and a second class of facets having Low Elevation (LE) angle characteristics.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates generally to holographic laser scanners of ultra-compact design capable of reading bar code symbols in point-of-sale (POS) and other demanding scanning environments.

2. Brief Description of the Prior Art

The use of bar code symbols for product and article identification is well known in the art.

Presently, various types of bar code symbol scanners have been developed. In general, these bar code symbol readers can be classified into two distinct classes.

The first class of bar code symbol reader simultaneously illuminates all of the bars and spaces of a bar code symbol with light of a specific wavelength(s) in order to capture an image thereof for recognition and decoding purposes. Such scanners are commonly known as CCD scanners because they use CCD image detectors to detect images of the bar code symbols being read.

The second class of bar code symbol reader uses a focused light beam, typically a focused laser beam, to sequentially scan the bars and spaces of a bar code symbol to be read. This type of bar code symbol scanner is commonly called a "flying spot" scanner as the focused laser beam appears as "a spot of light that flies" across the bar code symbol being read. In general, laser bar code symbol scanners are subclassified further by the type of mechanism used to focus and scan the laser beam across bar code symbols.

Polygon-based laser scanning systems employ lenses and moving (i.e. rotating or oscillating) polygon mirrors and/or other optical elements in order to focus and scan laser beams across bar code symbols during code symbol reading operations. Examples of such polygon-based laser scanning systems is described in U.S. Pat. Nos. 4,006,343; 4,093,865; 4,960,985; 5,073,702; 5,229,588; and JP-54-33740, each incorporated herein by reference in its entirety.

Holographic-based laser scanning systems employ lenses and moving (i.e. rotating) holographic elements and/or other optical elements in order to focus and scan laser beams across bar code symbols during code symbol reading operations. Examples of such holographic-based laser scanning systems is described in U.S. Pat. Nos. 4,415,224; 4,758,058; 4,748,316; 4,591,242; 4,548,463; 4,652,732; 4,794,237; 4,647,143; 5,331,445; 5,416,505; 5,475,207; 5,705,802; 5,837,988; and JP64-48017, each incorporated herein by reference in its entirety.

In demanding retail scanning environments, it is common to employ polygon-based laser scanning systems that have both bottom and side scanning windows to enable highly aggressive scanner performance, whereby the cashier need only drag a bar coded product past these scanning windows for the bar code thereon to be automatically read with minimal assistance of the cashier or checkout personal. Such dual scanning window systems are typically referred to as "bioptical" laser scanning systems as such systems employ two sets of optics disposed behind the bottom and side scanning windows thereof. Examples of polygon-based bioptical laser scanning systems are disclosed in U.S. Pat. Nos. 5,206,491; 5,229,588; 5,684,289; 5,705,802; 5,801,370; and 5,886,336, each incorporated herein by reference in its entirety.

In general, prior art bioptical laser scanning systems are generally more aggressive that conventional single scanning window systems. For this reason, bioptical scanning system are often deployed in demanding retail environments, such as supermarkets and high-volume department stores, where high check-out throughput is critical to achieving store profitability and customer satisfaction.

While prior art bioptical scanning systems represent a technological advance over most single scanning window system, prior art bioptical scanning systems in general suffered from various shortcomings and drawbacks.

In particular, by virtue of the dual scanning windows and supporting optics required by prior art bioptical laser scanning systems, such scanning systems have been physically larger than many retail environments would otherwise desire, as space near the point-of-sale is the most valuable space within the retail environment. Also, the laser scanning patterns of prior art bioptical laser scanning systems are not optimized in terms of scanning coverage and performance, and are generally expensive to manufacture by virtue of the large number of optical components presently required to constructed such laser scanning systems.

Thus, there is a great need in the art for an improved bioptical-type laser scanning bar code symbol reading system, while avoiding the shortcomings and drawbacks of prior art laser scanning systems and methodologies.

OBJECTS AND SUMMARY OF THE PRESENT INVENTION

Accordingly, a primary object of the present invention is to provide a novel bioptical-type holographic laser scanning system which is free of the shortcomings and drawbacks of prior art bioptical laser scanning systems and methodologies.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein a plurality of pairs of quasi-orthogonal laser scanning planes are projected within predetermined regions of space contained within a 3-D scanning volume defined between the bottom and side scanning windows of the system.

Another object of the present invention is to provide a novel bioptical holographic laser scanning system, wherein the plurality of pairs of quasi-orthogonal laser scanning planes are produced using a holographic scanning disc having holographic scanning facets that have high and low elevation angle characteristics as well as left, right and zero skew angle characteristics.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein the each pair of quasi-orthogonal laser scanning planes comprises a plurality of substantially-vertical laser scanning planes for reading bar code symbols having bar code elements (i.e. ladder-type bar code symbols) that are oriented substantially horizontal with respect to the bottom scanning window, and a plurality of substantially-horizontal laser scanning planes for reading bar code symbols having bar code elements (i.e. picket-fence type bar code symbols) that are oriented substantially vertical with respect to the bottom scanning window.

Another object of the present invention is to provide a bioptical holographic laser scanning system comprising a plurality of laser scanning stations, each of which produces a plurality of pairs of quasi-orthogonal laser scanning planes are projected within predetermined regions of space contained within a 3-D scanning volume defined between the bottom and side scanning windows of the system.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein the plurality of pairs of quasi-orthogonal laser scanning planes are produced using a holographic scanning disc supporting holographic scanning facets having high and low elevation angle characteristics and left, right and zero skew angle characteristics.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein each laser scanning station produces a plurality of pairs of quasi-orthogonal laser scanning planes which can read bar code symbol that is orientated with bar code elements arranged in either a substantially vertical (i.e. picket-fence) or substantially horizontal (i.e. ladder) configuration with respect to the horizontal scanning window of the system.

Another object of the present invention is to provide such a bioptical holographic laser scanning system employing four laser scanning systems, wherein the first and third laser scanning stations employ mirror groups and scanning facets having only high elevation characteristics and left and right skew angle characteristics so as to produce from each station a plurality of pairs of quasi-orthogonal laser scanning planes capable of reading bar code symbol orientated with bar code elements arranged in either a substantially vertical (i.e. picket-fence) or substantially horizontal (i.e. ladder) configuration with respect to the horizontal scanning window of the system.

Another object of the present invention is to provide such a bioptical holographic laser scanning system, wherein the second laser scanning station employs mirror groups and scanning facets having only low elevation characteristics and zero skew angle characteristics so as to produce from each station a plurality of pairs of quasi-orthogonal laser scanning planes capable of reading bar code symbol orientated with bar code elements arranged in either a substantially vertical (i.e. picket-fence) or substantially horizontal (i.e. ladder) configuration with respect to the horizontal scanning window of the system.

Another object of the present invention is to provide such a bioptical holographic laser scanning system, wherein the fourth laser scanning station employs mirror groups and scanning facets having only high elevation characteristics and zero skew angle characteristics so as to produce from each station a plurality of laser scanning planes capable of reading bar code symbol orientated with bar code elements arranged in either a substantially vertical (i.e. picket-fence) configuration with respect to the horizontal scanning window of the system.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein the plurality of pairs of quasi-orthogonal laser scanning planes are produced using S-polarized laser beams directed incident the holographic scanning disc.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein four symmetrically placed visible laser diodes (VLDs) are used to create the plurality of pairs of quasi-orthogonal laser scanning planes.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein a single VLD is used to create the vertical window scan pattern, thereby minimizing crosstalk.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein the sizes of the laser beam folding mirrors employed at each laser scanning station of the present invention are minimized.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein blocking of light return paths by the laser beam folding mirrors has been eliminated.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein mechanical interference between individual laser beam folding mirrors within the system has been eliminated.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein the angles of incidence of the laser scanning beams at the horizontal scanning window have been optimized.

Another object of the present invention is to provide a bioptical holographic laser scanning system which generates a laser scanning pattern providing 360 degrees of scan coverage at a POS station, while the internal mirror-space volume of the scanning system has been minimized.

Another object of the present invention is to provide such a bioptical holographic laser scanning system, wherein the "sweet spot" of the 360 laser scanning pattern is located at and above the center of the horizontal (i.e. bottom) scanning window, regardless of the item orientation or location of the bar code on the item.

Another object of the present invention is to provide such a bioptical holographic laser scanning system, wherein the center of all groups of laser scanning planes generated by the system is directed toward the center of the horizontal scanning window, or to a line normal to the horizontal scanning window at the center thereof, thereby enhancing operator productivity by providing the feedback "beep" at substantially the same location above the horizontal scanning window for each and every item being scanned.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein the size of the scan data collecting photodetector at each laser scanning station is minimized.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein the location of the scan data collecting photodetector at each laser scanning station is determined using a novel spreadsheet-based design process that minimizes the vertical space required for placement of the parabolic light collection mirror beneath the scanning disc.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein the size, shape and orientation of the scan data collecting photodetector at each laser scanning station is designed so that the lateral shift of the reflected beam image across the light sensitive surface of the photo detector, as a scanned item moves through the depth of field of the scanning region of the scanning station, which results in a relatively uniform light level reaching the light sensitive surface of the photodetector.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein the shift of the collected light across the data detector (as the item moves through the depth of field of the scanning region) minimizes variation in signal.

Another object of the present invention is to provide a bioptical holographic laser scanning system comprising a holographic scanning disc with multiple facets which simultaneously focus multiple scanning beams to overlapping regions in the 3-D scanning volume at varying focal distances (preferably, less than 2 inches or less difference in focal distance), which minimizes the effects of paper noise.

Another object of the present invention is to provide a bioptical holographic laser scanning system, which allows the same facets to be used for both the horizontal and vertical windows even though the distances to the items to be scanned is different for the two windows.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein use of a 12 facet disk design to increase the signal level for a 6 inch disk, necessary for POS scanners, which must provide lower laser power levels at the scan windows.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein use of an S-polarized beam at the disk to maximize signal and provide better resolution throughout the DOF region.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein use of skew facets with symmetric Left/Right skew, which allows the same scan pattern to be produced by both the fore and aft scanning stations.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein the vertical-window horizontal scan lines and the operator-side-station horizontal scan lines are split and tilted for enhanced scan coverage.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein recessing selected portions of the scanner base plate allow reduction of the box height.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein parabolic mirror with modified, non-sector-shaped, cross-section maximize light collection efficiency.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein use of optimum skew angle for each of the skew facets provides maximum scan coverage while minimizing the mirror-space volume.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein diffraction angles are selected to provide maximum scan coverage while still allowing complete blockage of the facet from undesired ambient light.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein a fixed beam blocker with optimum shape prohibits ambient light from entering the facets at the zero order beam angle, which light would otherwise be directed to the data detector by the parabolic mirror thereby increasing the noise level.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein undercut box design allows for a smaller scanner footprint in both the X-dimension and the Y-dimension.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein turning the VLD off when the scan line is no longer in the window, thereby eliminating unwanted internal scattering of the laser light and extends the life of the laser.

Another object of the present invention is to provide a bioptical holographic laser scanning system capable of generating a complex of pairs of quasi-orthogonal laser scanning planes, each composed by a plurality of substantially-vertical laser scanning planes for reading bar code symbols having bar code elements (i.e. ladder-type bar code symbols) that are oriented substantially horizontal with respect to the bottom scanning window, and a plurality of substantially-horizontal laser scanning planes for reading bar code symbols having bar code elements (i.e. picket-fence type bar code symbols) that are oriented substantially vertical with respect to the bottom scanning window.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein each scan data collecting photodetector is positioned behind a beam folding mirror having a small hole formed therethrough to allow the return light from a parabolic mirror beneath the scanning disc to reach the photodetector, thereby enabling optimum placement of the photodetector and nearly maximum use of the surface of the beam folding mirror for light collection while providing a light shield for the data detector.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein the light collection efficiency of each scanning facet is optimized in order to compensate for variations in facet collection area during laser scanning operations.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein a beam deflecting mirror is supported on the back side of each parabolic collection mirror, beneath a notch formed therein, to allow an incident laser beam, produced beyond the scanning disc, to be directed through the light collection mirror and onto the point of incidence of the scanning disc during scanning operation.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein a single beam folding mirror is used as the last outgoing mirror to produce a plurality of different laser scanning planes that are projected out through the vertical scanning window, thereby allowing greater light collection for a given amount of space (or potentially less space).

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein a light pipe or other light guiding structure can be used to conduct collected light at a point of collection within the system, and guiding such light to a photodetector located at a convenient location within the system.

Another object of the present invention is to provide a bioptical holographic laser scanning system, wherein a light-collection cone can be used to reduce the size of the photodetector.

Another object of the present invention is to provide a bioptical holographic laser scanning system which produces a three-dimensional laser scanning volume that is substantially greater than the volume of the housing of the holographic laser scanner itself, and provides full omni-directional scanning within the laser scanning volume.

A further object of the present invention is to provide such a bioptical holographic laser scanning system, in which the three-dimensional laser scanning volume has multiple focal planes and a highly confined geometry extending about a projection axis extending from the scanning windows of the holographic scanning system.

A further object of the present invention is to provide such a bioptical holographic laser scanning system, in which laser light produced from a particular holographic optical element reflects off a bar code symbol, passes through the same holographic optical element, and is thereafter collimated for light intensity detection.

A further object of the present invention is to provide such a bioptical holographic laser scanning system, in which a plurality of lasers simultaneously produce a plurality of laser beams which are focused and scanned through the scanning volume by a rotating disc that supports a plurality of holographic facets.

A further object of the present invention is to provide such a bioptical holographic laser scanning system, in which the holographic optical elements on the rotating disc maximize the use of the disk space for light collection, while minimizing the laser beam velocity at the focal planes of each of the laser scan patterns, in order to minimize the electronic bandwidth required by the light detection and signal processing circuitry.

A further object of the present invention is to provide a compact bioptical holographic laser scanning system, in which substantially all of the available light collecting surface area on the scanning disc is utilized and the light collection efficiency of each holographic facet on the holographic scanning disc is substantially equal, thereby allowing the holographic laser scanner to use a holographic scanning disc having the smallest possible disc diameter.

A further object of the present invention is to provide such a bioptical holographic laser scanning system, in which laser beam astigmatism caused by the inherent astigmatic difference in each visible laser diode is effectively eliminated prior to the passage of the laser beam through the holographic optical elements on the rotating scanning disc.

A further object of the present invention is to provide such a bioptical holographic laser scanning system, in which the dispersion of the relatively broad spectral output of each visible laser diode by the holographic optical elements on the scanning disc is effectively automatically compensated for as the laser beam propagates from the visible laser diode, through an integrated optics assembly, and through the holographic optical elements on the rotating disc of the holographic laser scanner.

A further object of the present invention is to provide such a bioptical holographic laser scanning system, in which a conventional visible laser diode is used to produce a laser scanning beam, and a simple and inexpensive arrangement is provided for eliminating or minimizing the effects of the dispersion caused by the holographic disc of the laser scanner.

A further object of the present invention is to provide such a bioptical holographic laser scanning system, in which the inherent astigmatic difference in each visible laser diode is effectively eliminated prior to the laser beam passing through the holographic optical elements on the rotating disc.

A further object of the present invention is to provide such a bioptical holographic laser scanning system, in which the laser beam produced from each laser diode is processed by a single, ultra-compact optics module in order to circularize the laser beam produced by the laser diode, eliminate the inherent astigmatic difference therein, as well as compensate for wavelength-dependent variations in the spectral output of each visible laser diode, such as superluminescence, multi-mode lasing, and laser mode hopping, thereby allowing the use of the resulting laser beam in holographic scanning applications demanding large depths of field.

A further object of the present invention is to provide such a bioptical holographic laser scanning system, in which an independent light collection/detection subsystem is provided for each laser diode employed within the holographic laser scanner.

A further object of the present invention is to provide such a bioptical holographic laser scanning system, in which an independent signal processing channel is provided for each laser diode and light collection/detection subsystem in order to improve the signal processing speed of the system.

A further object of the present invention is to provide such a bioptical holographic laser scanning system, in which a plurality of signal processors are used for simultaneously processing the scan data signals produced from each of the photodetectors within the holographic laser scanner.

A further object of the present invention is to provide such a bioptical holographic laser scanning system, in which each facet on the holographic disc has an identification code which is encoded by the zero-th diffraction order of the outgoing laser beam and detected so as to determine which scanning planes are to be selectively filtered during the symbol decoding operations.

A further object of the present invention is to provide such a bioptical holographic laser scanning system, in which the zero-th diffractive order of the laser beam which passes directly through the respective holographic optical elements on the rotating disc is used to produce a start/home pulse for use with stitching-type decoding processes carried out within the scanner.

These and other objects of the present invention will become apparent hereinafter and in the Claims to Invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more fully understand the Objects of the Present Invention, the following Detailed Description of the Illustrative Embodiments should be read in conjunction with the accompanying Figure Drawings in which:

FIG. 1A1 is a perspective view of the bioptical holographic laser scanning system of the present invention showing its bottom and side scanning windows formed with its compact scanner housing;

FIG. 1A2 is an elevated side view of the bioptical holographic laser scanning system of FIG. 1A;

FIG. 1B1 is a perspective view of the bioptical holographic laser scanning system of the present invention shown installed in a Point-Of-Sale (POS) retail environment

FIG. 1B2 is an exploded perspective view of the bioptical holographic laser scanning system of the present invention shown installed in a Point-Of-Sale (POS) retail environment

FIG. 1C is a perspective view of the bioptical holographic laser scanning system of the present invention shown installed above a work surface (e.g. a conveyor belt structure) employed, for example, in manual sortation operations or the like;

FIG. 1D1 is a perspective view of the bioptical holographic scanning system of the illustrative embodiment of the present invention, shown with the top panels of its housing removed in order to reveal the holographic scanning disc mounted on its optical bench, and the first, second, third and fourth laser scanning stations disposed thereabout, wherein each laser scanning station comprises a laser beam production module, a set of laser beam folding mirrors, a light collecting/focusing mirror disposed beneath the scanning disc, a photodetector disposed above the scanning disc, and pair of analog/digital signal processing boards associated with the laser scanning station;

FIG. 1D2 is a perspective view of a wire-frame graphics model of the bioptical holographic scanning system of FIG. 1D, wherein the components thereof are shown using wire-frame modeling and the bottom and side scanning windows are indicated in dotted lines;

FIG. 1E is a plane view of the bioptical holographic scanning system shown in FIG. 1D;

FIG. 1F is a perspective view of the scanner housing employed in the bioptical holographic scanning system of FIG. 1E, show with its top cover panels removed therefrom;

FIG. 1G is a perspective view of the optical bench employed in the bioptical holographic scanning system of FIG. 1D;

FIG. 1H is a perspective view of the optical bench employed in the bioptical holographic scanning system of FIG. 1D;

FIG. 2A1 is a perspective view of the bioptical holographic scanning system of the illustrative embodiment of the present invention, shown with its housing removed in order to reveal the holographic scanning disc rotatably mounted on its optical bench, and the first, second, third and fourth laser scanning stations disposed thereabout, wherein each laser scanning station comprises a laser beam production module, a set of laser beam folding mirrors, a light collecting/focusing mirror disposed beneath the scanning disc, a photodetector disposed above the scanning disc, and pair of analog/digital signal processing boards associated with the laser scanning station;

FIG. 2A2 is a perspective view of the bioptical holographic scanning system shown in FIG. 2A1, wherein the components thereof are shown using wire-frame graphics modeling and the bottom and side scanning windows are indicated in dotted lines;

FIG. 2B1 is a plan view of the bioptical holographic scanning system of the illustrative embodiment shown in FIG. 2A1;

FIG. 2B2 is a plan view of graphics the bioptical holographic scanning system shown in FIG. 2A1, wherein the components thereof are shown using wire-frame graphics modeling and the bottom and side scanning windows are indicated in dotted lines;

FIG. 2C1 is a first elevated side view of the bioptical holographic scanning system of FIG. 2A1, taken along the longitudinally extending reference plane passing through the axis of rotation of the scanning disc axis and disposed normal to the bottom scanning window indicated in dotted lines, wherein the components thereof are shown using solid modeling while the side scanning window is not shown;

FIG. 2C2 is a first elevated side view of the bioptical holographic scanning system shown in FIG. 2C1, wherein the components thereof are shown using wire-frame graphics modeling and the bottom and side scanning windows are indicated in dotted lines;

FIG. 2D1 is a second elevated side view of the bioptical holographic scanning system of FIG. 2A1, taken along the longitudinally extending reference plane passing through the axis of rotation of the scanning disc axis and disposed normal to the bottom scanning window indicated in dotted lines, wherein the components thereof are shown using solid modeling while the side scanning window is not shown;

FIG. 2D2 is a second elevated side view of the bioptical holographic scanning system shown in FIG. 2D1, wherein the components thereof are shown using wire-frame graphics modeling and the bottom and side scanning windows are indicated in dotted lines;

FIG. 2E1 is a third elevated side view of the bioptical holographic scanning system of FIG. 2A1, taken along the longitudinally extending reference plane passing through the axis of rotation of the scanning disc axis and disposed normal to the bottom scanning window indicated in dotted lines, wherein the components thereof are shown using solid modeling while the side scanning window is not shown;

FIG. 2E2 is a third elevated side view of the bioptical holographic scanning system shown in FIG. 2E1, wherein the components thereof are shown using wire-frame graphics modeling and the bottom and side scanning windows are indicated in dotted lines;

FIG. 2F1 is a perspective view of a subassembly from the bioptical holographic scanning system of the illustrative embodiment, comprising the optical bench of the system, the holographic scanning disc mounted thereon, the first, second, third and fourth laser beam production modules mounted about the perimeter of the holographic scanning disc, and the first, second, third and fourth associated parabolic light collection mirror structures mounted beneath the holographic scanning disc, adjacent the respective laser beam production modules;

FIG. 2F2 is a plan view of the subassembly of FIG. 2F2, showing the subcomponents thereof using wire-frame modeling;

FIG. 2G1 is a perspective view of the laser beam production module employed in each of the laser scanning stations in the biopticals holographic laser scanning system of FIG. 1A, wherein the components thereof are shown using solid graphics modeling techniques;

FIG. 2G2 is cross-sectional view of the laser beam production module depicted in FIG. 2G1, showing its subcomponents using wire-frame modeling techniques, as well as the propagation of the laser beam from its visible laser diode source, through its multi-function light diffractive grating, and reflected off its light reflective mirror, out towards the laser beam deflecting mirror adjacent the holographic scanning disc;

FIG. 2G3 is a cross-sectional view of the laser beam production module shown in FIGS. 2G1 and 2G2;

FIG. 2H1 is a perspective view of the laser beam deflection module employed in each of the laser scanning stations in the biopticals holographic laser scanning system of FIG. 1A, wherein the components thereof are shown using solid graphics modeling techniques;

FIG. 2H2 is a perspective view of the laser beam deflection module employed in each of the laser scanning stations in the biopticals holographic laser scanning system of FIG. 1A, using wire-frame graphics modeling techniques to show the spatial location of the subcomponents thereof within the laser beam reflection module;

FIG. 2I1 is an elevated side view of the holographic laser scanning disc and laser scanning stations associated with the bioptical holographic laser scanning system depicted in FIG. 1A, using wire-frame modeling techniques to show the position of the photodetector directly above the point of incidence of the laser beam on each holographic scanning disc in each laser scanning station thereof;

FIG. 2I2 is an elevated side view of the holographic laser scanning disc, a light blocking element, and laser scanning stations of the bioptical holographic laser scanning system depicted in FIG. 1A, using wire-frame modeling techniques to show the position of the light blocking element with respect to the holographic scanning disc, the bottom window, and the photodetectors in each laser scanning station thereof;

FIG. 2I3 is a perspective view of a wire frame model of the holographic laser scanning disc and light blocking element of FIG. 2I2;

FIG. 2J1 is a plan view of the holographic laser scanning disc and laser scanning stations associated with the bioptical holographic laser scanning system depicted in FIG. 1A, using solid graphics modeling techniques to show the position of the photodetector directly above the point of incidence of the laser beam on the holographic scanning disc in each laser scanning station thereof;

FIG. 2J2 is a plan view of the holographic laser scanning disc and laser scanning stations associated with the bioptical holographic laser scanning system depicted in FIG. 1A, using wire-frame graphics modeling techniques to show the position of the photodetector directly above the point of incidence of the laser beam on the holographic scanning disc in each laser scanning station thereof;

FIG. 2K is a perspective view of the first laser scanning station (ST1) in the bioptical holographic laser scanning system of the present invention, showing solid models of its laser beam production and direction modules disposed about the edge of the holographic laser scanning disc, and associated first, second and third groups of laser beam folding mirrors, wherein the laser beam folding mirrors associated with the first group (M.sub.i,j,k where the group index j is i=1) cooperate with laser beams generated from scanning facets having high elevation angle and positive (i.e. left) skew angle characteristics, the laser beam folding mirrors associated with the second group (M.sub.i,j,k where the group index j is j=2) cooperate with laser beams generated from scanning facets having high elevation angle and negative (i.e. right) skew angle characteristics, and the laser beam folding mirrors associated with the first group (M.sub.i,j,k where the group index j is j=3) cooperate with laser beams generated from scanning facets having low elevation angle and zero (i.e. no) skew angle characteristics;

FIG. 2L is a perspective view of the second laser scanning station (ST2) in the bioptical holographic laser scanning system of the present invention, showing solid models of its laser beam production and direction modules disposed about the edge of the holographic laser scanning disc, and associated group of laser beam folding mirrors, wherein the laser beam folding mirrors associated the group (M.sub.i,j,k where the group index j is j=3) cooperate with laser beams generated from scanning facets having low elevation angle and zero (i.e. no) skew angle characteristics;

FIG. 2M is a perspective view of the third laser scanning station (ST3) in the bioptical holographic laser scanning system of the present invention, showing solid models of its laser beam production and direction modules disposed about the edge of the holographic laser scanning disc, and associated first, second and third groups of laser beam folding mirrors, wherein the laser beam folding mirrors associated with the first group (M.sub.i,j,k where the group index j is i=1) cooperate with laser beams generated from scanning facets having high elevation angle and positive (i.e. left) skew angle characteristics, the laser beam folding mirrors associated with the second group (M.sub.i,j,k where the group index j is j=2) cooperate with laser beams generated from scanning facets having high elevation angle and negative (i.e. right) skew angle characteristics, and the laser beam folding mirrors associated with the first group (M.sub.i,j,k where the group index j is j=3) cooperate with laser beams generated from scanning facets having low elevation angle and zero (i.e. no) skew angle characteristics;

FIG. 2N is an elevated side view of the first and third laser scanning stations (ST1 and ST3) in the bioptical holographic laser scanning system of the present invention, showing solid models of its laser beam production and direction modules disposed about the edge of the holographic laser scanning disc, and associated first, second and third groups of laser beam folding mirrors;

FIG. 2O is a perspective view of the first and third laser scanning stations (ST1 and ST3) in the bioptical holographic laser scanning system of the present invention, showing solid models of its laser beam production and direction modules disposed about the edge of the holographic laser scanning disc, and associated first, second and third groups of laser beam folding mirrors;

FIG. 2P is a perspective view of the fourth laser scanning station (ST4) in the bioptical holographic laser scanning system of the present invention, showing solid models of its laser beam production and direction modules disposed about the edge of the holographic laser scanning disc, and associated first, second and third groups of laser beam folding mirrors, wherein the laser beam folding mirrors associated with the first group (M.sub.i,j,k where the group index j is i=1) cooperate with laser beams generated from scanning facets having high elevation angle and positive (i.e. left) skew angle characteristics, the laser beam folding mirrors associated with the second group (M.sub.i,j,k where the group index j is j=2) cooperate with laser beams generated from scanning facets having high elevation angle and negative (i.e. right) skew angle characteristics, and the laser beam folding mirrors associated with the first group (M.sub.i,j,k where the group index j is j=3) cooperate with laser beams generated from scanning facets having low elevation angle and zero (i.e. no) skew angle characteristics;

FIG. 2Q is an elevated side view of the fourth laser scanning stations (ST4) in the bioptical holographic laser scanning system of the present invention, showing solid models of its laser beam production and direction modules disposed about the edge of the holographic laser scanning disc, and associated first, second and third groups of laser beam folding mirrors;

FIG. 3A2 is a geometrical optics model of the process of producing the P(i,j)-th laser scanning plane of the system by directing the output laser beam from the j-th laser beam production module through i-th holographic scanning facet supported upon the holographic scanning disc as it rotates about its axis, wherein various parameters employed in the model, including diffraction angle, beam elevation angle and scan angle, are schematically defined;

FIG. 3A3 is a plan view of the geometrical optics model of FIG. 3A2, defining the skew angle of the scanning facet, also employed therein;

FIG. 3A4 is a table categorizing the twelve facets on the holographic scanning disc of the illustrative embodiment as either having (i) high elevation angle characteristics and left (i.e. positive) skew angle characteristics, (ii) high elevation angle characteristics and right (i.e. negative) skew angle characteristics and (iii) low elevation angle characteristics and no (i.e. zero) skew angle characteristics;

FIG. 3B provides a vector-based specification of the vertices of each laser beam folding mirrors employed in the first laser scanning station (ST1) of the bioptical holographic scanning system using position vectors defined with respect to local coordinate reference system R.sub.local 1 symbolically embedded within the holographic scanning disc, as shown in FIG. 2A1;

FIG. 3C provides a vector-based specification of the vertices of each laser beam folding mirrors employed in the second laser scanning station (ST2) of the bioptical holographic scanning system using position vectors defined with respect to local coordinate reference system R.sub.local 2 symbolically embedded within the holographic scanning disc, as shown in FIG. 2A1;

FIG. 3D provides a vector-based specification of the vertices of each laser beam folding mirrors employed in the third laser scanning station (ST3) of the bioptical holographic scanning system using position vectors defined with respect to local coordinate reference system R.sub.local 3 symbolically embedded within the holographic scanning disc, as shown in FIG. 2A;

FIG. 3E provides a vector-based specification of the vertices of each laser beam folding mirrors employed in the fourth laser scanning station (ST4) of the bioptical holographic scanning system using position vectors defined with respect to local coordinate reference system R.sub.local 4 symbolically embedded within the holographic scanning disc, as shown in FIG. 2A1;

FIGS. 3F1 and 3F2, taken together, provide a table setting forth major physical, optical and electrical parameters which can be used to characterize to the bioptical holographic laser scanning system of the illustrative embodiment of the present invention;

FIGS. 3G1A through 3G2B, taken collectively, provide a table setting forth various physical and optical parameters characteristic of the holographic laser scanning disc employed in the illustrative embodiment of the bioptical holographic laser scanning system of the present invention;

FIGS. 3H1 through 3H3, taken collectively, provide a table setting forth the holographic exposure/recording angles (i.e. facet construction parameters) for mastering at 488 nanometers the holographic laser scanning disc employed in the illustrative embodiment of the bioptical holographic laser scanning system of the present invention;

FIGS. 311 and 312, taken together, provide a table setting forth the "modified" holographic exposure/recording angles (i.e. facet construction parameters) for mastering at 488 nanometers the holographic laser scanning disc employed in the illustrative embodiment, while correcting/compensating for post-processing residual gelatin swell associated with the holographic recording medium;

FIGS. 3J1 and 3J2, taken together, provide a table setting forth parameters used to analyze the focus shift and out-of-focus spot size for a converging laser reference beam;

FIG. 3K is a table setting forth the focal distances of each scanning facet on the holographic scanning disc of the illustrative embodiment of the present invention, as well as optical distances from each facet to the horizontal and vertical windows of the bioptical holographic scanning system of the illustrative embodiment;

FIGS. 3L1A through 3L2B, collectively, provide a table setting forth CDRH/IEC calculations which verify that the bioptical holographic laser scanning system of the illustrative embodiment satisfies Laser Class requirements;

FIGS. 4A, 4B and 4C set forth a block functional diagram of bioptical holographic laser scanning system of the illustrative embodiment of the present invention, showing the major components of the system and their relation to each other;

FIG. 5A1 is a perspective view of the bioptical holographic laser scanning system of the illustrative embodiment of the present invention, schematically illustrating the projection of each and every P(i,j)-th laser scanning plane generated within the three-dimensional scanning volume extending between the bottom and side scanning windows of the system during each complete revolution of the holographic laser scanning disc, wherein the prespecified depth of focus (DOF) and laser beam cross-section characteristics of each such laser scanning plane are specified by the holographic scanning facet generating the laser scanning plane;

FIG. 5A2 is an elevated side view of the bioptical holographic laser scanning system of the illustrative embodiment of the present invention, schematically illustrating the projection of each and every P(i,j)-th laser scanning plane generated within the three-dimensional scanning volume extending between the bottom and side scanning windows of the system during each complete revolution of the holographic laser scanning disc, wherein the prespecified depth of focus (DOF) and laser beam cross-section characteristics of each such laser scanning plane are specified by the holographic scanning facet generating the laser scanning plane;

FIG. 5A3 is a plan view of the bioptical holographic laser scanning system of the illustrative embodiment of the present invention, schematically illustrating the projection of each and every P(i,j)-th laser scanning plane generated within the three-dimensional scanning volume extending between the bottom and side scanning windows of the system during each complete revolution of the holographic laser scanning disc, wherein the prespecified depth of focus (DOF) and laser beam cross-section characteristics of each such laser scanning plane are specified by the holographic scanning facet generating the laser scanning plane;

FIG. 5A4 is an elevated side end view of the bioptical holographic laser scanning system of the illustrative embodiment of the present invention, schematically illustrating the projection of each and every P(i,j)-th laser scanning plane generated within the three-dimensional scanning volume extending between the bottom and side scanning windows of the system during each complete revolution of the holographic laser scanning disc, wherein the prespecified depth of focus (DOF) and laser beam cross-section characteristics of each such laser scanning plane are specified by the holographic scanning facet generating the laser scanning plane;

FIG. 5A5 is a second elevated side view of the bioptical holographic laser scanning system of the illustrative embodiment of the present invention, schematically illustrating the projection of each and every P(i,j)-th laser scanning plane generated within the three-dimensional scanning volume extending between the bottom and side scanning windows of the system during each complete revolution of the holographic laser scanning disc, wherein the prespecified depth of focus (DOF) and laser beam cross-section characteristics of each such laser scanning plane are specified by the holographic scanning facet generating the laser scanning plane;

FIG. 5B1 is a perspective view of the bioptical holographic laser scanning system of the illustrative embodiment of the present invention, schematically illustrating the projection of substantially vertically-disposed laser scanning planes through the bottom scanning window for reading horizontally-oriented (i.e. ladder-type) bar code symbols, when scanning facets (Nos. 7, 9 and 11) having high elevation angle characteristics and left (i.e. positive) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning beams that reflect off the first group of beam folding mirrors (MG1@ST1) associated therewith during system operation;

FIG. 5B2 is a side view of the bioptical holographic laser scanning system of the illustrative embodiment of the present invention, schematically illustrating the projection of substantially vertically-disposed laser scanning planes through the bottom scanning window for reading horizontally-oriented (i.e. ladder-type) bar code symbols, when scanning facets (Nos. 7, 9 and 11) having high elevation angle characteristics and left (i.e. positive) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning beams that reflect off the first group of beam folding mirrors (MG1@ST1) associated therewith during system operation;

FIG. 5B3 is a plan view of the bioptical holographic laser scanning system of the illustrative embodiment of the present invention, schematically illustrating the projection of substantially vertically-disposed laser scanning planes through the bottom scanning window for reading horizontally-oriented (i.e. ladder-type) bar code symbols, when scanning facets (Nos. 7, 9 and 11) having high elevation angle characteristics and left (i.e. positive) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning beams that reflect off the first group of beam folding mirrors (MG1@ST1) associated therewith during system operation;

FIG. 5B4 is an elevated end view of the bioptical holographic laser scanning system of the illustrative embodiment of the present invention, schematically illustrating the projection of substantially vertically-disposed laser scanning planes through the bottom scanning window for reading horizontally-oriented (i.e. ladder-type) bar code symbols, when scanning facets (Nos. 7, 9 and 11) having high elevation angle characteristics and left (i.e. positive) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning beams that reflect off the first group of beam folding mirrors (MG1@ST1) associated therewith during system operation;

FIG. 5B5 is an elevated side view of the bioptical holographic laser scanning system of the illustrative embodiment of the present invention, schematically illustrating the projection of substantially vertically-disposed laser scanning planes through the bottom scanning window for reading horizontally-oriented (i.e. ladder-type) bar code symbols, when scanning facets (Nos. 7, 9 and 11) having high elevation angle characteristics and left (i.e. positive) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning beams that reflect off the first group of beam folding mirrors (MG1@ST1) associated therewith during system operation;

FIG. 5C1 is a perspective view of a wire-frame model of the laser scanning platform within the bioptical holographic laser scanning system of the illustrative embodiment, schematically illustrating the projection of substantially vertically-disposed laser scanning planes through the bottom scanning window for reading horizontally-oriented (i.e. ladder-type) bar code symbols, when scanning facets (Nos. 7, 9 and 11) having high elevation angle characteristics and left (i.e. positive) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning beams that reflect off the first group of beam folding mirrors (MG1@ST1) associated therewith during system operation;

FIG. 5C2 is a plan view of a wire-frame model of the laser scanning platform within the bioptical holographic laser scanning system of the illustrative embodiment, schematically illustrating the projection of substantially vertically-disposed laser scanning planes through the bottom scanning window for reading horizontally-oriented (i.e. ladder-type) bar code symbols, when scanning facets (Nos. 7, 9 and 11) having high elevation angle characteristics and left (i.e. positive) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning beams that reflect off the first group of beam folding mirrors (MG1@ST1) associated therewith during system operation;

FIG. 5C3 is an elevated end view of a wire-frame model of the laser scanning platform within the bioptical holographic laser scanning system of the illustrative embodiment, schematically illustrating the projection of substantially vertically-disposed laser scanning planes through the bottom scanning window for reading horizontally-oriented (i.e. ladder-type) bar code symbols, when scanning facets (Nos. 7, 9 and 11) having high elevation angle characteristics and left (i.e. positive) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning beams that reflect off the first group of beam folding mirrors (MG1@ST1) associated therewith during system operation;

FIG. 5C4 is a first elevated side view of a wire-frame model of the laser scanning platform within the bioptical holographic laser scanning system of the illustrative embodiment, schematically illustrating the projection of substantially vertically-disposed laser scanning planes through the bottom scanning window for reading horizontally-oriented (i.e. ladder-type) bar code symbols, when scanning facets (Nos. 7, 9 and 11) having high elevation angle characteristics and left (i.e. positive) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning beams that reflect off the first group of beam folding mirrors (MG1@ST1) associated therewith during system operation;

FIG. 5C5 is a second elevated side view of a wire-frame model of the laser scanning platform within the bioptical holographic laser scanning system of the illustrative embodiment, schematically illustrating the projection of substantially vertically-disposed laser scanning planes through the bottom scanning window for reading horizontally-oriented (i.e. ladder-type) bar code symbols, when scanning facets (Nos. 7, 9 and 11) having high elevation angle characteristics and left (i.e. positive) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning beams that reflect off the first group of beam folding mirrors (MG1@ST1) associated therewith during system operation;

FIG. 5D1 is a perspective view of the bioptical holographic laser scanning system of the illustrative embodiment of the present invention, schematically illustrating the projection of substantially vertically-disposed laser scanning planes through the bottom scanning window for reading horizontally-oriented (i.e. ladder-type) bar code symbols, when scanning facets (Nos. 8, 10 and 12) having high elevation angle characteristics and right (i.e. negative) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning beams that reflect off the second group of beam folding mirrors (MG2@ST1) associated therewith during system operation;

FIG. 5D2 is a side view of the bioptical holographic laser scanning system of the illustrative embodiment of the present invention, schematically illustrating the projection of substantially vertically-disposed laser scanning planes through the bottom scanning window for reading horizontally-oriented (i.e. ladder-type) bar code symbols, when scanning facets (Nos. 8, 10 and 12) having high elevation angle characteristics and right (i.e. negative) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning beams that reflect off the second group of beam folding mirrors (MG2@ST1) associated therewith during system operation;

FIG. 5D3 is a plan view of the bioptical holographic laser scanning system of the illustrative embodiment of the present invention, schematically illustrating the projection of substantially vertically-disposed laser scanning planes through the bottom scanning window for reading horizontally-oriented (i.e. ladder-type) bar code symbols, when scanning facets (Nos. 8, 10 and 12) having high elevation angle characteristics and right (i.e. negative) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning beams that reflect off the second group of beam folding mirrors (MG2@ST1) associated therewith during system operation;

FIG. 5D4 is an elevated end view of the bioptical holographic laser scanning system of the illustrative embodiment of the present invention, schematically illustrating the projection of substantially vertically-disposed laser scanning planes through the bottom scanning window for reading horizontally-oriented (i.e. ladder-type) bar code symbols, when scanning facets (Nos. 8, 10 and 12) having high elevation angle characteristics and right (i.e. negative) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning beams that reflect off the second group of beam folding mirrors (MG2@ST1) associated therewith during system operation;

FIG. 5D5 is a second side view of the bioptical holographic laser scanning system of the illustrative embodiment of the present invention, schematically illustrating the projection of substantially vertically-disposed laser scanning planes through the bottom scanning window for reading horizontally-oriented (i.e. ladder-type) bar code symbols, when scanning facets (Nos. 8, 10 and 12) having high elevation angle characteristics and right (i.e. negative) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning beams that reflect off the second group of beam folding mirrors (MG2@ST1) associated therewith during system operation;

FIG. 5E1 is a perspective view of a wire-frame model of the laser scanning platform within the bioptical holographic laser scanning system of the illustrative embodiment, schematically illustrating the projection of substantially vertically-disposed laser scanning planes through the bottom scanning window for reading horizontally-oriented (i.e. ladder-type) bar code symbols, when scanning facets (Nos. 8, 10 and 12) having high elevation angle characteristics and right (i.e. negative) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning beams that reflect off the second group of beam folding mirrors (MG2@ST1) associated therewith during system operation;

FIG. 5E2 is a plan view of a wire-frame model of the laser scanning platform within the bioptical holographic laser scanning system of the illustrative embodiment, schematically illustrating the projection of substantially vertically-disposed laser scanning planes through the bottom scanning window for reading horizontally-oriented (i.e. ladder-type) bar code symbols, when scanning facets (Nos. 8, 10 and 12) having high elevation angle characteristics and right (i.e. negative) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning beams that reflect off the second group of beam folding mirrors (MG2@ST1) associated therewith during system operation;

FIG. 5E3 is an elevated end view of a wire-frame model of the laser scanning platform within the bioptical holographic laser scanning system of the illustrative embodiment, schematically illustrating the projection of substantially vertically-disposed laser scanning planes through the bottom scanning window for reading horizontally-oriented (i.e. ladder-type) bar code symbols, when scanning facets (Nos. 8, 10 and 12) having high elevation angle characteristics and right (i.e. negative) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning beams that reflect off the second group of beam folding mirrors (MG2@ST1) associated therewith during system operation;

FIG. 5E4 is a first elevated side view of a wire-frame model of the laser scanning platform within the bioptical holographic laser scanning system of the illustrative embodiment, schematically illustrating the projection of substantially vertically-disposed laser scanning planes through the bottom scanning window for reading horizontally-oriented (i.e. ladder-type) bar code symbols, when scanning facets (Nos. 8, 10 and 12) having high elevation angle characteristics and right (i.e. negative) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning beams that reflect off the second group of beam folding mirrors (MG2@ST1) associated therewith during system operation;

FIG. 5E5 is a second elevated side view of a wire-frame model of the laser scanning platform within the bioptical holographic laser scanning system of the illustrative embodiment, schematically illustrating the projection of substantially vertically-disposed laser scanning planes through the bottom scanning window for reading horizontally-oriented (i.e. ladder-type) bar code symbols, when scanning facets (Nos. 8, 10 and 12) having high elevation angle characteristics and right (i.e. negative) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning beams that reflect off the second group of beam folding mirrors (MG2@ST1) associated therewith during system operation;

FIG. 5F1 is a perspective view of the bioptical holographic laser scanning system of the illustrative embodiment of the present invention, schematically illustrating the projection of substantially horizontally-disposed laser scanning planes through the bottom scanning window for reading vertically-oriented (i.e. picket-fence type) bar code symbols, when scanning facets (Nos. 1 through 4) having low elevation angle characteristics and no (i.e. zero) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning beams that reflect off the third group of beam folding mirrors (MG3@ST1) associated therewith during system operation;

FIG. 5F2 is a plan view of the bioptical holographic laser scanning system of the illustrative embodiment of the present invention, schematically illustrating the projection of substantially horizontally-disposed laser scanning planes through the bottom scanning window for reading vertically-oriented (i.e. picket-fence-type) bar code symbols, when scanning facets (Nos. 1 through 4) having low elevation angle characteristics and no (i.e. zero) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning beams that reflect off the third group of beam folding mirrors (MG3@ST1) associated therewith during system operation;

FIG. 5F3 is an end view of the bioptical holographic laser scanning system of the illustrative embodiment of the present invention, schematically illustrating the projection of substantially horizontally-disposed laser scanning planes through the bottom scanning window for reading vertically-oriented (i.e. picket-fence type) bar code symbols, when scanning facets (Nos. 1 through 4) having low elevation angle characteristics and no (i.e. zero) skew angle characteristics pass through the first laser scanning station (ST1) and generate laser scanning