Mirrorless scanners with movable laser, optical and sensor components.

CROSS-REFERENCE TO RELATED APPLICATION

0001This application is a continuation-in-part of Application Serial No. 07/193,265 filed May 11, 1988.

BACKGROUND OF THE INVENTION

1. Field of the Invention

0002This invention generally relates to laser scanner systems for reading indicia of different light reflectivity such as bar code symbols and, more particularly, to so-called mirrorless scanner systems wherein system components, other than mirrors, are employed to effect sweeping or scanning of symbols to be read.

2. Description of Related Art

0003Laser scanner systems and components of the type exemplified by U.S. Pat. Nos. 4,251,798; 4,360,798; 4,369,361; 4,387,297; 4,593,186; 4,496,831; 4,409,470; 4,460,120; 4,607,156; 4,673,803; 4,736,095; 4,758,717; 4,816,660; 4,808,804; 4,816,661; 4,760,248; 4,871,904; 4,806,742; 4,845,350, as well as U.S. Appln. Ser. Nos. 148,669 and 147,708 -- all of said patents and patent applications being owned by the assignee of the instant invention and being incorporated by reference herein -- have generally been designed to read indicia having parts of different light reflectivity, e.g. bar code symbols, particularly of the Unversal Product Code (UPC) type, at a certain working or reading distance from a hand-held or stationary scanner.

0004Typically, a light source such as a laser generates a light beam which is optically modified to form a beam spot of a certain size at the working distance and is directed by optical components along a light path toward a bar code symbol located in the vicinity of the working distance for reflection from the symbol. A photodetector having a field of view extending across and slightly past the symbol detects light of variable intensity reflected off the symbol and generates electrical signals indicative of the detected light. These electrical signals are decoded into data descriptive of the symbol. A scanning component is situated in the light path. The scanning component may either sweep the beam spot across the symbol and trace a scan line across and past the symbol, or scan the field of view of the photodetector, or do both.

0005In any case, the scanner typically includes a moving mirror. For example, U.S. Pat. No. 4,251,798 discloses a rotating polygon having a planar mirror at each side, each mirror tracing a scan line across the symbol. U.S. Pat. Nos. 4,387,297 and 4,409,470 both employ a planar mirror which is repetitively and reciprocally driven in alternate circumferential directions about a drive shaft on which the mirror is mounted. U.S. Patent No. 4,816,660 discloses a multi-mirror construction composed of a generally concave mirror portion and a generally planar mirror portion, the multi-mirror construction being repetitively and reciprocally driven in alternate circumferential directions about a drive shaft on which the multi-mirror construction was mounted.

0006No matter what the shape or orientation of the mirror, the known scanning components employed in laser scanning systems moved mirrors to perform the aforementioned sweeping and scanning actions. Moving other laser scanning system components was not thought to be practical. Thus, moving a gas laser tube was unthinkable, particularly in hand-held, compact system applications, due to the large size and the requisite large room necessary to accommodate a moving gas laser tube. Moving an optical lens was also not thought to be desirable, because optical alignment is critical in laser scanning systems. Hence, it was the mirror that was typically designated to effect the sweeping/scanning functions. However, in some laser scanning applications, mirror movements have not been found to be altogether desirable.

0007In non-laser scanning systems of the type exemplified by U.S. Pat. No. 4,578,571, a non-laser light emitting diode, an optical assembly, a photodetector, and electronic preamplifier/filter circuitry are all fixedly mounted on a common support that is connected to a cantilevered bimorph which is reciprocatingly driven to jointly move all the aforementioned components back and forth over a bar code symbol to be scanned. The large volume and heavy mass of all the commonly-mounted non-laser system components requires the expenditure of a great deal of power for the drive. This is not altogether practical in those cases, e.g. battery-powered operation, where power consumption is to be held to a minimum. Also, moving only one or more non-mirrored system components relative to another for conserving power was heretofore not considered desirable, because of the optical alignment problems described above.

0008The components for the light scanning system, including the light source, optics, photodetector, scanning component and an electrical conductor, are mounted together in a common assembly to constitute a compact, lightweight, scan module. The scan module is mounted in an interchangeable, modular manner in housings of different configurations.

0009For example, the housing can be hand-held and shaped as a cylinder in a so-called flashlight-type configuration, or shaped as a box, or shaped with a gun-like configuration. The housing can be mounted on the back of an operator's arm (see, for example, U.S. 4,766,299) or on one or more fingers of the operator's hand, typically with the aid of a strap, a clip, or a glove. The housing can be mounted on the operator's arm, typically adjacent or on the wrist. The housing can be mounted in a countertop workstation. The housing can be mounted in a mobile cart, or shopping cart, or, in some cases, even in a stationary installation.

0010The compact, lightweight nature of the scan module enables myriad other housing configurations to be fashioned. Thus, the scan module can be mounted anywhere on an operator's person, e.g. in a helmet to be worn on the operator's head, in eyeglasses to be worn in front of the operator's eyes, in a shoulder or body harness, etc.

SUMMARY OF THE INVENTION

1. Objects of the Invention

0011It is a general object of this invention to advance the state of the art of scanner systems for reading indicia of different light reflectivity, particularly laser scanner systems for reading bar code symbols.

0012Another object of this invention is to eliminate the use and the movement of mirrors to effect sweeping and scanning actions.

0013A further object of this invention is to provide a so-called "mirrorless" scanner system which is compact in size, light in weight, reliable in use, and relatively inexpensive to assemble and manufacture.

0014Still another object of this invention is to move one or more scanner system components either jointly or separately relative to one another to effect the sweeping and scanning actions.

0015Yet another object of this invention is to employ the mirrorless scanner system in a plurality of hand-held, finger-held, arm-held, body-held, desk-top workstation, mobile or stationary configurations.

0016A still further object of this invention is to employ a mirrorless scanner system in a plurality of scanning modes, such as single and multi-axis scanning.

0017Another object of this invention is to interchangeably mount the mirrorless scanner system in housings of different configurations.

2. Features of the Invention

0018In keeping with these objects, and others which will become apparent hereinafter, one feature of this invention resides, briefly stated, in a mirrorless scanner arrangement in a light scanning system for reading indicia having parts of different light reflectivity, e.g. bar code symbols having alternating bars and spaces. The system is of the general type which includes a light source component, e.g. a laser, for emitting a laser light beam; an optical component, e.g. a focusing lens and/or an aperture stop, for optically modifying and directing the laser beam along an optical path toward the symbol located in the vicinity of a reference plane exteriorly of the system; and a photodetector component, e.g. a photodiode, having a field of view and operative for detecting at least a portion of light of variable intensity along a return path reflected off the symbol, and for generating an electrical signal indicative of the detected light intensity. This electrical signal is thereupon processed and converted to data descriptive of the symbol.

0019In accordance with this invention, the mirrorless scanner arrangement includes means for mounting at least one of the components for repetitive, reciprocating movement relative to at least another of the components, as well as drive means for repetitively, reciprocatingly moving the mounting means and said at least one component to scan at least one of said light beam and said field of view. Only one or only two of said components can advantageously be reciprocated relative to said other components. In addition, all the components can be jointly reciprocated, in which event, it is advantageous if the optical and return paths are co-linear, at least within a housing in which all the aforementioned components are housed.

0020Advantageously, the drive means includes a motor having an elongated shaft, and operative for reciprocatingly turning the shaft about an axis which extends along the elongation of the shaft in alternate circumferential directions over arc lengths less than 360°, e.g. 10° to either side of a center position. Said at least one component is mounted on the shaft for joint turning movement therewith.

0021The component mounted on the shaft may be the laser, e.g. a semiconductor laser diode, a focusing lens, an aperture stop, the combination of a focusing lens and an aperture stop, or the entire combination of the diode, the lens and the aperture stop. Also, the photodiode could be mounted on the shaft for joint turning movement therewith. Since the diode requires a power supply, e.g. a 12-volt DC source, and since the electrical signal developed by the photodiode must be conveyed to signal processing circuitry, electrical coiled tensile wires are advantageously connected to the laser diode and the photodiode.

0022Rather than turning the aforementioned components about an axis, the drive means may also be operative to reciprocatingly move one or more of said components in a plane which is perpendicular to an optical axis along which the optical path extends in a center position. Such planar movement can be effected by many types of drives, e.g. an electromagnetic drive, a mechanical drive, a piezoelectric drive, and a bi-metallic heating drive.

0023The mirrorless scanner arrangement of this invention can be used to generate a single scan line over the symbol to be read, or can be used with other scanner components to generate a multi-line scan pattern over the symbol.

0024In addition, the mirrorless scanner arrangement is very compact in size and light in weight, and can be mounted in modular manner in many different system configurations. For example, the arrangement can be mounted in hand-held housings having any convenient shape, e.g. a gun-shaped head having a barrel and a handle, or a box-like head, or a cylindrical-type head, or in wrist-held or arm-held housings, or in glove-like housings, or in finger-held housings, e.g. a ring-shaped head, or in desk-top or countertop housings, e.g. a workstation having scan-above, scan-down, or scan-sideways capabilities, or in mobile, cart-mounted housings, or in stationary system installations, e.g. mounted at a production line or at a cash register. The compact size and lightweight characteristic renders the arrangement very versatile for multiple applications and uses. The power requirements for reciprocating the one or more components to be reciprocated is minimal. Advantageously, the arrangement is easily removable from the system in which it is installed. An arrangement requiring replacement is easily interchangeable with another.

0025The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, best will be understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

0026<ul id="ul0001" list-style="none"><li>FIG. 1A is a partly broken-away, partly sectioned side view of a hand-held light scanning system in which a mirrorless scanner arrangement in accordance with this invention is housed;</li><li>FIG. 1B is an end view of FIG. 1A;</li><li>FIG. 2 is a front perspective view of the mirrorless scanner arrangement of FIG. 1A;</li><li>FIG. 3 is a partly sectioned side view of a mirrorless scanner arrangement in accordance with another embodiment of this invention;</li><li>FIG. 4 is a diagrammatic top plan view of the embodiment of FIG. 3 depicting its operation;</li><li>FIG. 5 is a partly sectioned side view of a mirrorless scanner arrangement in accordance with yet another embodiment of this invention;</li><li>FIG. 6 is an enlarged view taken on line 6--6 of FIG. 5;</li><li>FIG. 7 is a diagrammatic top plan view of the embodiment of FIG. 5 depicting its operation at two end-limiting positions.</li><li>FIG. 8 is a rear perspective view of the mirrorless scanner arrangement of FIG. 2 as employed in a multi-axis scanning system;</li><li>FIG. 9 is a partly broken-away perspective view of an additional embodiment of the mirrorless scanner arrangement in accordance with this invention;</li><li>FIG. 10 is a side view of a gooseneck-type scanning system workstation for use with any of the mirrorless scanner arrangements of this invention;</li><li>FIG. 11 is a side view of still another embodiment of a mirrorless scanner arrangement in accordance with this invention;</li><li>FIG. 12 is a sectional view taken along line 12--12 of FIG. 11;</li><li>FIG. 13 is a cross-sectional view of an alternate spring for use in the embodiment of FIGs. 11 and 12;</li><li>FIG. 14 is a sectional view taken on line 14--14 of FIG. 16;</li><li>FIG. 15 is an end view of the embodiment of FIG. 16;</li><li>FIG. 16 is a top plan view of an additional embodiment of a mirrorless scanner arrangement in accordance with this invention;</li><li>FIG. 17 is a view analogous to FIG. 14, but of another embodiment of a mirrorless scanner arrangement in accordance with this invention;</li><li>FIG. 18 is a view analogous to FIG. 14, but of still another embodiment of a mirrorless scanner arrangement in accordance with this invention;</li><li>FIG. 19 is a view analogous to FIG. 14, but of yet another embodiment of a mirrorless scanner arrangement;</li><li>FIG. 20 is a partly broken-away, perspective view of a hand-held scanning system for use with the mirrorless scanning arrangement;</li><li>FIG. 21 is a perspective view of a hand-held, swivel-type scanning system for use with the mirrorless scanning arrangement;</li><li>FIG. 22 is a partly broken-away, sectional view of a hand-held scanning system for use with the mirrorless scanning arrangement;</li><li>FIG. 23 is a side view of FIG. 22;</li><li>FIG. 24 is a side view of an arm-held scanning system for use with the mirrorless scanning arrangement;</li><li>FIG. 24A is a front perspective view of another arm-held acanning system for use with the mirrorless scanning arrangement;</li><li>FIG. 24B is a side perspective view of still another arm-held scanning system for use with the mirrorless scanning arrangement;</li><li>FIG. 25 is a side view of a glove-like scanning system worn on a user's hand;</li><li>FIG. 26 is a side view of a finger-held, ring-type scanning system for use with the mirrorless scanning arrangement;</li><li>FIG. 27 is a perspective view of a mobile, checkout stand for use with the mirrorless scanning arrangement;</li><li>FIG. 28 is a side view of a hand-held scanning system for use with the mirrorless scanning arrangement, as mounted on a shopping cart;</li><li>FIG. 29 is an enlarged sectional view taken on line 29--29 of FIG. 28;</li><li>FIG. 30 is a perspective view of a countertop scanning system at a point-of-transaction site;</li><li>FIG. 31 is a side view of a countertop scanning system with a detachable head; and</li><li>FIG. 32 is a top plan view of a scanning system adapted to accommodate right- and left-handed users.</li></ul>

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

0027Referring now to the drawings, reference numeral 10 in FIGs. 1A and 1B generally identifies an arrangement in a scanner system of the type generally described in the above identified patents and patent applications, the entire contents of all of which are hereby incorporated by reference herein, for reading symbols, particularly UPC bar code symbols. As used in this specification and the following claims, the term "symbol" is intended to be broadly construed and to cover not only symbol patterns composed of alternating bars and spaces, but also other patterns, as well as alpha-numeric characters and, in short, any indicia having portions of different light reflectivity.

0028The arrangement 10 comprises a hand-held housing 12 having a base 14 which subdivides the interior of the housing into an upper half 16 and a lower half 18. A lightweight, high-speed, miniature scanning motor 20 similar to that described in U.S. Pat. No. 4,496,831 is mounted on base 14. The motor 20 has an output shaft 22 which is repetitively driven in alternate circumferential directions about an axis along which the shaft extends over arc lengths less than 360° in each direction. Structural, functional and operational aspects of the motor 20 and of control circuitry 24 for the motor are set forth in detail in U.S. Pat. No. 4,496,831 and, hence, for the sake of brevity, will not be repeated herein.

0029One difference between the motor 20 of this invention and the motor of U.S. Pat. No. 4,496,831 is the superstructure that is mounted on the output shaft 22. Instead of a planar mirror as taught by said patent, the invention proposes, in FIG. 1A, mounting a generally U-shaped support 26 at the end of the shaft 22, and mounting a laser/optics subassembly 28 on the support 26. The subassembly 28 and the support 26 are jointly oscillated and turned with the shaft 22.

0030The subassembly 28 includes an elongated hollow tube 30, a laser diode 32 fixedly mounted at one axial end region of the tube 30, a lens barrel 34 mounted at the opposite axial end region of the tube 30, and a focusing lens 36 mounted within the barrel (see FIG.3). The focusing lens 36 is preferably a plano-convex lens, but may be spherical, convex or cylindrical as well. The barrel 34 has an end wall formed with an aperture stop 38 which is an opening extending through the end wall. The barrel 34 is mounted for longitudinal telescoping movement within and along the tube 30. The lens 36 is situated adjacent the end wall of the barrel and is mounted for joint movement with the barrel. The position of the barrel and, in turn, of the lens relative to the diode is fixed typically by gluing or clamping, at the assembly site so that a known distance between the lens and the aperture stop, on the one hand, and between the lens, the aperture stop and the diode, on the other hand, is obtained. A coil spring 37 (see FIG. 3) is located within and extends along the barrel and tube, and has one coil end bearing against the diode, and another coil end bearing against a planar side of the lens. The spring urges the lens against the end wall having the aperture stop, thereby fixedly locating the lens relative to the aperture stop.

0031The subassembly 28, per se, forms no part of this invention and, in fact, is described and claimed in U.S. Patent No. 4,816,660 to which reference can be had for further structural, functional and operational aspects of the subassembly. It is sufficient for this invention to understand that the subassembly 28 includes a solid-state laser diode 32 operative for propagating and generating an incident laser beam, either in the invisible or visible light range, and the combination of a focusing lens and an aperture stop together operative for focusing the laser beam to have a beam cross-section or beam spot of a certain waist size within a range of working distances relative to the housing 12. The focused beam passes through the aperture stop 38 and through a scan window 40 on the housing in the vicinity of a reference plane located exteriorly of the housing within the range of working distances along an outgoing optical path.

0032During the alternate, repetitive oscillations of the shaft 22, the support 26 and the subassembly 28 likewise participate in this oscillatory movement, thereby causing the beam spot to be swept in an arc whose center of curvature is located at the diode across the symbol at the reference plane and to trace a curved scan line thereat. Hence, no longer is a mirror used to effect sweeping of a beam spot across a symbol, but, instead, other scanner components are moved and, in the embodiment of FIG. 1A, these other components comprise the laser diode 32 and the optical components which are jointly turned as a unitary structure about an axis parallel to the reference plane.

0033A portion of the light reflected off the symbol passes along a return path through a second window 42 on the housing in the direction of arrow B to a photodetector 44 for detecting the variable intensity of the returning portion of the reflected laser light over a field of view, and for generating an electrical analog signal indicative of the detected variable light intensity. In the FIG. 1A embodiment, the photodetector 44 is stationarily mounted on the printed circuit board 46. Printed circuit boards 48 and 50 at either side of board 46 contain signal processing circuitry 52 and microprocessor control circuitry 53 for converting the analog electrical signal to a digital signal, and for processing the digital signal to data descriptive of the symbol being read. Details of the signal processing and microprocessor control circuitry can be had by reference to the above-identified patents and applications.

0034A two-part multi-wire plug-in cable connector 54 has one part electrically connected to the signal processing and microprocessor control circuitry and another part electrically connected to a flexible multi-wire cable 54' connected to a display 55 and a keyboard 56. A rechargeable battery pack 58 supplies power to the laser diode and the electrical circuitry in the housing. By moving only the laser diode and the optical component relative to the stationary photodetector, power from the battery pack is conserved.

0035Means for initiating reading may advantageously include a trigger 60 mounted on the housing 12. The trigger extends in part outwardly of the housing to be manually actuated by a user who is holding the housing 12 in his hand. The trigger is operatively connected through trigger switch 62 and actuates the laser diode 32, the motor 20, the photodetector 44, the signal processing circuitry 52 and the control circuitry 53 to initiate a reading of the symbol. The trigger is actuated once for each symbol to be read, each symbol in its respective turn. Once the control circuitry determines that the symbol has been successfully decoded, the control circuitry terminates the reading of the symbol and deactuates the previously actuated components in the housing and readies the system for the next symbol.

0036FIG. 2 illustrates the various electrical, mechanical and optical components assembled as a modular unit prior to mounting in the upper half 16 of the housing 12 of FIGs. 1A, 1B. The electrical circuitry on the printed circuit boards 46, 48, 50, as well as on base 14, has been omitted from FIG. 2 for the sake of clarity.

0037Turning now to FIG. 3, like parts with that of FIG. 1A have been identified with like reference numerals. The oscillating motor 20, once again, has an output shaft 22 on which a generally U-shaped support 26 is mounted. A laser/optics subassembly 28 is mounted on one leg 64 of the support. A photodetector 44 is mounted on another leg 66 of the support. Coiled tensile wire groups 68, 70 connect the diode 32 and the photodetector 44 to the non-illustrated electrical circuitry on printed circuit board 48. Although coiled wires have been illustrated, other types of electrical connectors, e.g. flat cable, could be employed. A collecting lens 72 is mounted on leg 64 and coaxially surrounds subassembly 28. The lens 72, the subassembly 28 and the photodetector 44 all have a common boresight or optical axis 74 along which the optical and return paths are co-linear, and are all oscillatable as a unit in alternate circumferential directions (see double-headed arrow 76 in FIG. 4) about the axis along which shaft 22 extends.

0038The operation of the FIG. 3 embodiment is schematically shown in FIG. 4. An incident laser beam is emitted from the subassembly 28. In a center position, this beam is directed along optical axis 74 to a reference plane 78 at which a symbol is located. Light is scattered in all directions from the symbol. A portion of the reflected light, as represented by light rays 79,81, is incident on collecting lens 72, e.g. a Fresnel lens, and focused onto an inlet of the photodetector 44. The inlet may be round, square or rectangular (see FIG.6). As the unit turns in the direction of either arrow 76, the beam spot at the reference plane likewise moves across the symbol. The returning light is always focused onto the inlet of the photodetector.

0039The FIG. 3 embodiment is retro-reflective because not only the incident beam, but also the field of view of the photodetector, are being simultaneously scanned across the symbol. By contrast, the FIGs. 1A, 1B embodiment is a so-called "flying spot" scanner, because only the incident beam is being swept across the symbol, the photodetector being stationary.

0040Turning now to the embodiment of FIGs. 5-7, like reference numerals again identify like parts. The oscillating motor 20, once again, has an output shaft 22 on which a support 80 is mounted. Rather than being U-shaped like support 26, support 80 is L-shaped and has an upright leg 82. A laser/optics subassembly 28 is mounted on leg 82. A photodetector 44 is stationarily mounted on printed circuit board 46. Coiled tensile wire group 68 interconnects the diode 32 and electrical circuitry on board 46. Collecting lens 72 is mounted on leg 82 in a coaxially surrounding relationship with subassembly 28. The lens 72 and the subassembly 28 turn as a unit in either direction of double-headed arrow 76, whereas photodetector 44, in contrast to the previous embodiment of FIG. 3, is stationary.

0041As schematically shown in FIG. 7, an incident light beam emitted from subassembly 28 is directed in one end-limiting position along optical axis 84 to impinge on a symbol located at the reference plane 78, whereupon a portion of the reflected light, as represented by light rays 86, 88, is incident on collecting lens 72 and focused at one end 90 of an elongated slot-like inlet 92 of the photodetector 44, best shown in FIG. 6. At an opposite end-limiting position, shown in phantom lines in FIG. 7, the collected portion of reflected light is focused at an opposite end 94 of the inlet 92. Between end-limiting portions, the collected, focused light travels lengthwise along the inlet 92.

0042The FIGS. 5-7 embodiment is another retro-reflective arrangement, because both the incident beam is being swept across the symbol, and the field of view of the photodetector is likewise being swept across the symbol at the same time due to the movement of the collecting lens. The collecting lens could be eliminated by having the output power of the light source sufficiently high.

0043As described so far, the various embodiments describe a single curved trace or scan line in one direction across the symbol being read. FIG. 8 shows an arrangement for generating a scan pattern extending in more than one direction over the symbol. Thus, as before, motor 20 repetitively drives output shaft 22, support 26 and laser/optics subassembly 28 in the alternate directions indicated by arrows 76. Tensile wire group 68 interconnects the diode 32 with a low voltage power supply 96. The motor and its superstructure are mounted on a horizontal platform 98 of a base 100.

0044The base has additional platforms for other components. Thus, horizontal platform 102 supports a collecting lens 104. Platform 106 supports a photodetector 44 on an upper surface, as well as a printed circuit board 108 on which signal processing circuitry is mounted on a lower surface.

0045A second motor 20' identical to motor 20 is mounted on a vertical platform 110 and has an output shaft 22' which is at right angles to shaft 22. Instead of the aforementioned superstructure, a planar mirror 112 is mounted at one end of shaft 22', thereby being similar to the scanning element described in U.S. Pat. No. 4,496,831. The motor 22' drives the mirror 112 in alternate circumferential directions as indicated by double-headed arrow 114.

0046In operation, with motors 22, 22' both oscillating the components mounted on their shafts, a scan pattern composed of multiple lines is generated over the symbol. Thus, with motor 20 generating a single scan line along an X-axis direction, motor 20' will move the single scan line along a Y-axis, thereby generating a set of mutually parallel lines extending across the pattern. By varying the speed, direction and frequency of the motors 20, 20', complex scan patterns, e.g. Lissajous patterns, can be generated.

0047Due to the oscillatory movement of the laser/optics subassembly 28, the tensile wires 68 interconnecting the diode and its power supply 96 are subjected to considerable stress. The mechanical integrity of the wire joints is weakened by such stress forces generated while the subassembly changes directions. Generally speaking, these stress forces are proportional to the distance between the shaft 22 and the point of the wire attachment to the subassembly.

0048FIG. 9 shows an arrangement wherein the wire joints between the diode and its power supply are positioned in the immediate vicinity of the shaft, thereby minimizing the stress forces acting to weaken such joints and maximizing the working lifetime of the arrangement.

0049Thus, a support block 26'' is mounted on the shaft 22, but off to one side of the shaft. The subassembly 28 is mounted on the block 26''. A printed circuit board 116 is mounted at the side of the block facing the shaft 22. The board 116 has three printed conductive strips 118<u>a</u>, 118<u>b</u>, 118<u>c</u> extending along the board 116. The laser diode 32 has a first group of wires 68 connected to respective ends of the strips; and a second group of wires 120 is connected to respective opposite ends of the strips and to the power supply 96. The subassembly 28, the board 116 and the first group of wires 68 are jointly oscillated. The second group of wires 120 is subjected to stress forces, but, as shown, the wire joints at the opposite ends of the strips are immediately adjacent the shaft 22 so that the magnitude of the stress forces is much reduced as compared to the situation wherein the first group of wires 68 were directly connected to the power supply 96.

0050FIG. 10 shows a desk-top workstation wherein a housing 121 generally having the same shape as the upper half of housing 12 in FIG. 1A is mounted above a base 123 situated on a generally horizontal support surface such as a tabletop 125. A gooseneck-type semi-rigid, bendable, conduit 127 interconnects the housing 121 with the base 123 and enables the housing to be manually bendably positioned in any desired orientation relative to the base and to be maintained in the desired orientation. The light beam emitted from the housing can thus be positioned at any desired angle relative to the symbol to be read.

0051Advantageously, the base 123 is hollow and contains signal processing circuitry which is connected by electrical wires running through the conduit 127 to the mirror scanning arrangement contained in the housing 121. Instead of the base, the end of the conduit remote from the housing 121 could be attached to a cash register, analogous point-of-sale apparatus, or a fixed mount, e.g. on a production line.

0052As described so far, the laser diode/optics subassembly 28 by itself or with the photodetector 44 is turned about an axis to effect a scanning or sweeping action. This invention also proposes moving the focusing lens 36 either by itself or with the aperture stop 28 relative to the diode 32 in a plane generally parallel to the light-emitting outlet of the diode.

0053Turning to FIG. 11, the laser diode 32 is stationarily mounted on a support 122. The diode 32 emits along optical axis 130 a wide-angle fan-shaped laser beam schematically represented by light rays 124, 126. The fan-shaped beam diverges at different angles in both orthogonal planes extending parallel to the plane of the diode outlet and perpendicular to the optical axis 130. The focusing lens 36 is mounted in a holder 128 at a fixed distance of focal length F as measured along axis 130, from the diode. The holder has an opening centered on the axis 130, the opening serving as the aperture stop 38.

0054The holder 128, as shown in FIG. 12, extends into a permanent magnet casing 132. A pair of convoluted diaphragm suspension springs 134, 136 support the holder 128 on the magnet casing 132. A voice coil 138 surrounds the holder 128 inside the casing 132 and is bounded by north N and south S poles of the casing.

0055By electrically energizing the coil 138, the holder and, in turn, the lens and the aperture stop are made to jointly reciprocate back and forth in a plane perpendicular to axes 130 due to electromagnetic attraction and repulsion farces generated at the coil. If the deflection of the lens and aperture stop as measured from the axis 130 to one end-limiting position is denoted D, then it can be shown that the deflected laser beam represented by light ray 140 is shifted by an angular distance<maths id="math0001"><math display="block"><mrow><mtext>A = tan⁻¹</mtext><mfrac><mrow><mtext>D</mtext></mrow><mrow><mtext>F</mtext></mrow></mfrac></mrow></math><img file="EP0513530A2_D0001.tif" /></maths> .

0056FIG. 13 shows an alternate to the convoluted springs 134, 136. A so-called "spider" spring 142 having curved legs 144 could also be used.

0057FIG. 14 shows another arrangement for reciprocally shifting the lens 36 and aperture stop 38 in a plane parallel to the plane of the outlet of the diode 32. The lens 36 is mounted on a bridge support 150 which spans the distance between, and is carried by, two center legs 152, 154 of E-shaped leaf springs 156, 158. Outer legs 160, 162 of spring 156 and outer legs 164, 166 of spring 158 are stationarily connected to an overhead support frame 170.

0058The bridge support 150 has an opening centered on optical axis 130, the opening serving as the aperture stop 38. A permanent magnet strip 172 having a north N pole at one end and a south S pole at an opposite end is carried by the bridge support. A pair of driving coils 174, 176 surrounds each pole.

0059In operation, each driving coil is electrically energized. Electromagnetic attraction and repulsion forces are generated by magnetic interaction between the coils and the poles N, S, thereby causing the bridge support to be reciprocally shifted in a plane perpendicular to axis 130. FIG. 14 shows this arrangement in a center, non-shifted position. By contrast, the FIG. 17 embodiment described below illustrates a shifted position. It will be noted that only the upper ends of the center legs of the E-springs are displaced. A substantially constant distance between the lens and aperture stop combination and the diode is maintained. Proper laser beam focus at the reference plane is thus maintained thereat.

0060As before, the shifting of the lens and aperture stop causes the laser beam emitted by the diode to be deflected at an angle<maths id="math0002"><math display="block"><mrow><mtext>A = tan⁻¹</mtext><mfrac><mrow><mtext>D</mtext></mrow><mrow><mtext>F</mtext></mrow></mfrac></mrow></math><img file="EP0513530A2_D0002.tif" /></maths> . The beam spot is moved along an arc around a center of curvature at the lens. It is possible, by having unequal lengths or stiffnesses in the legs of the springs, to have the beam spot moved in a desired manner across the symbol. For example, the spot can be moved in a straight line.

0061Rather than using electromagnetic means, other means can be used to displace the lens and aperture stop. FIG. 17 shows an arrangement identical to FIG. 14, but, instead of the magnetic strip 172, a plate 180 is connected to the bridge support. The plate 180 has a lug 182 to which a drive bar 184 is pivotably connected. The bar 184 can be connected to a pure mechanical drive, an electro-mechanical drive, or a piezo-electric substrate, i.e. a transducer operative for converting electrical to mechanical energy, to effect the reciprocal movement.

0062In another variant, the center legs 152, 154 of the springs can be made of one bi-metallic material while the outer legs are made of another bi-metallic material. Heating all the legs would cause the center legs to be displaced relative to the outer legs.

0063In FIGs. 14-17, since the aperture stop 38 moves with the lens 36, the output power of the laser beam will decrease at the ends of the scan line, because the intensity of the unfocused laser beam is brightest on the axis 130. This loss of power at the ends of the scan could be compensated electrically by sensing the output power of the beam, or the light reflected off the rear surface of the aperture stop, and by adjusting the electrical supply current to the laser diode so as to maintain a constant power output.

0064Another approach is shown in FIG. 18, wherein the aperture stop 38 is held stationary, and only the focusing lens 36 is reciprocally shifted. Since the laser beam does not pass through the center of the lens 36 when the lens is shifted off axis, the deflection or scan angle A is amplified. Light passing through the lens off the axis 130 has more optical aberrations, but they have not been found to be significant for bar code reading applications.

0065The low mass of the moving structure, i.e. the lens alone; the lens and aperture stop together; the lens, aperture stop and diode jointly; and the lens, aperture stop, diode and photodetector jointly, enables the system to operate at resonance for low power applications, as well as off resonance. Very high scanning speeds on the order of 40 scans per second and more are obtainable due to the low mass of the moving structure.

0066Yet another approach is shown in FIG. 19, wherein the focusing lens 36 is held stationary, and only the aperture stop 38 is reciprocally shifted. The aperture stop 38 is formed as an opening in a top wall 200 that is positioned by side walls 202, 204 at a distance from a support 206 on which the laser diode 32 is mounted. The apertured top wall 200 is shiftable to the left and to the right, as indicated by the phantom lines, by any reciprocating drive, e.g. an electromagnet or piezo-electric drive. Bimorph material can also be used for the walls 200, 202, 204 to move the aperture stop in a plane in front of the lens 36.

0067FIG. 20 shows the compact laser/optics subassembly 28 mounted on the reciprocating motor 20, as described above, installed in a hand-held housing 210 equipped with a display 212 and a keyboard 214. The housing 210 has a rectangular cross-section and, at its top, is provided with a superstructure that enables scanning to be performed to the right or, in another mode of operation, to the left of the housing.

0068The housing 210 has a top rectangular wall 216 fixedly mounted in place with the aid of four screws 218 at the corners of the top wall. A hood 220 is mounted at one end of the top wall. A stationary reflecting mirror 222 is located within the confines of the hood above the top wall 216. A scan window 224 closes the interior of the hood from the environment. The mirror 222 is positioned in the path of the emitted laser beam emanating from the laser/optics subassembly 28, and redirects the laser beam toward one side, e.g. toward the right side, of the housing. Returning light from the symbol being read passes through the window 224 and is collected by photodetector 44.

0069By removing the four screws 218, turning the superstructure by 180°, replacing the screws 218, the scanning arrangement will work just as described above, except that, this time, the mirror 222 will redirect the laser beam toward the other side, e.g. toward the left side, of the housing. In this way, right- and left-handed users can be accommodated.

0070To the same effect is the structure shown in FIG. 21 in which the emitted beam can also be directed toward the right or the left. A housing 226 of cylindrical cross-section has a circular top wall 228 on which a hood 230 is supported. A reflecting mirror identical to mirror 222 is mounted within hood 230. A scan window 232 closes the hood 230. An L-shaped locking lug 234 depends from the top wall 228 and, in the illustrated position, lockingly engages a hook 236 provided on the circular side wall of the housing 226. The same laser/optics subassembly shown in FIG. 20 is mounted within housing 226. The laser beam is propagated toward the right in FIG. 21.

0071To accommodate the user, the top wall 228 and hood 230 can be turned to the position shown in phantom lines until the lug 234 engages another non-illustrated hook spaced 180° away from hook 236. In this locked position, the laser beam is propagated toward the left in FIG. 21. The swiveling of a locking lug to engage one or the other of two hooks with a snap-type action is somewhat easier to perform than the removal and replacement of screws as described for FIG. 20.

0072In all of the various embodiments, the mirrorless scanning arrangement is very compact in size. This allows the arrangement to be fabricated as a module that can be installed in many different types of laser scanning systems. The module advantageously comprises a laser/optics subassembly mounted on a support such as a reciprocating scan component, together with a photodetector, all of which are connected to an electrical connector to enable the module to be electrically connected to other electrical components.

0073As shown in FIGs. 22 and 23, the mirrorless scanning arrangement is mounted in a cylindrical flashlight-type housing 250. In the preferred embodiment, the diameter of the housing 250 is on the order of one inch. Otherwise, like parts have been identified with like numerals.

0074The trigger switch 62 is located on the circuit board 48 and has an operating button or trigger 60 which projects slightly through the cylindrical side wall of the housing. The trigger 60 is positioned to be engaged and depressed by the user's fingers, particularly the thumb, as illustrated.

0075The laser/optics subassembly 28 directs the laser beam through a circular window 252 at a nose end of the housing 250. Reflected light from the symbol returns through the window 252 and is detected by photodetector 54.

0076The on-board battery pack 58 is advantageously mounted at a rear end of the housing 250.

0077As shown in FIG. 24, any of the above-described mirrorless scanning arrangements can be mounted in a box-shaped housing 254 which is mounted on the user's arm adjacent the wrist 256 by a strap 258 that at least partially encircles the wrist. The strap 258 is preferably composed of multiple expandible links, but can also be constituted of an elastomeric material, or a rigid material whose opposite ends are detachably interconnected, similar to a belt or a watch band.

0078Reading is initiated either automatically by object recognition, or manually by movement of the hand of the operator. For example, a trigger switch 260 has an elongated armature 262 pivotably mounted on, and laterally offset from, the housing 254. The armature 262 extends into the space formed between the forefinger and the thumb of the operator. The operator's fingers pivot the armature 262 to initiate reading. For ergonometric reasons, it is preferred if the armature 262 is positioned closer to the forefinger, as shown in solid lines in FIG. 24, so that the armature can be displaced upwards, or if the armature 262 is positioned closer to the thumb, as shown in dashed lines in FIG. 24, so that the armature can be displaced downwards.

0079As shown in FIG. 24A, another arm-held housing 251 is mounted adjacent and encircles wrist 256 by means of a strap 253. A keyboard 255 for data entry, as well as a display 257 for displaying information, are positioned on the housing 251 so as to face the operator. An exit window 259 is positioned adjacent the wrist and laterally offset from the back of the operator's hand to allow an outgoing light beam and/or reflected light to pass laterally thereof. A trigger switch 261 is pivotably mounted in the housing 251 adjacent the wrist and in the path of outward movement of the back of the operator's hand when the wrist is flexed relative to the arm. In a preferred use, the operator points his or her out-stretched forefinger 263 toward the symbol to be read, and swings the forefinger, together with the whole hand by flexing the wrist 256, freely in space between the points P1 and P2 so as to trace the symbol.

0080As shown in FIG. 24B, still another arm-held housing 265 is mounted adjacent and encircles wrist 256 by means of a strap 267. A keyboard 269 and a display 271 are positioned on the housing 265. In this case, the exit window is positioned adjacent the wrist and elevated above the back of the operator's hand to allow an outgoing light beam and/or reflected light to pass thereover. A trigger switch 273 is pivotably mounted on the housing adjacent the wrist and in the path of inward movement of the hand during wrist flexure. Again, the operator points outstretched finger 263 toward the symbol 275, and swings the forefinger, together with the whole hand, freely in space between points P3 and P4 so as to trace the symbol.

0081In addition to the embodiments, in which a lever switch may be employed to initiate scanning, a switch may also be provided on the strap which mounts the scanner/terminal on the wrist to perform the scanning initiating function. Such switch when mounted on the inside of the strap so that the switch may be activated by appropriate user motion.

0082As an alternative to a lever or other pressure operated switch, electronic activation may be utilized to initiate scanning. Object sensing (i.e., triggering when an object is proximate to the scanner), or voice activation (i.e., triggering when the user says "scan") may also be used.

0083The "glove" approach allows functional modules in addition to scanning to be added or deleted with relative ease. Such modules may include functions such as keyboard, display, communications, power supply, memory, and data storage, printer, or alternative reader technologies (e.g., magnetic stripe) which can be interchangeably attached or detached from electrical connectors disposed the glove. The glove also allows appropriate fixed positioning of such modules so that they may be most conveniently accessed and utilized by the user. As an example, as shown in Figure 24A the display may be positioned on the inside of the arm or wrist, and a keyboard positioned so that it is more easily accessed.

0084The arrangements of FIGs. 24A, 24B serve as complete, independent data terminals.

0085Turning now to FIG. 25, a box-shaped housing 277, analogous to housing 254 of FIG. 24, is incorporated in a glove 279 that is worn on the operator's hand. The glove 279 is preferably composed of an elastomeric material. The housing has a base support 281 that is embedded in the glove and rests above the back of the operator's hand between the knuckles and the wrist. The outgoing light beam and/or returning reflected light pass over the operator's fingers. Reading is initiated either automatically by object recognition, or manually by movement of the operator's hand. For example, clenching the hand can cause a pressure sensor embedded in the glove to generate a trigger signal for initiating reading.

0086Turning now to FIG. 26, a finger-held housing 264 containing the scanning arrangement is supported on at least one of the user's fingers 266 by a ring-like support 268. A particularly compact scanning arrangement, in which the light source and the scanning component are implemented on a single semiconductor and/or electro-optical substrate, is described in pending U.S. application Serial No.          , filed      , the entire contents of which are incorporated herein by reference. The outgoing light beam passes over the user's fingers and, as before, reading can be automatically or manually initiated.

0087FIG. 27 illustrates a mobile checkout stand in which the scanning arrangement is incorporated, together with other point-of-transaction accessories. The stand 270 includes a wheeled carriage 272 which supports the scanning arrangement underneath an X-shaped window 274 located in a planar top wall of the carriage, a keyboard 276 for entering data relating to a product bearing the symbol being scanned, an overhead display 278 for displaying data relating to the product, a weighing scale 280 for weighing the product, a printer 282 for printing a paper tape receipt or labels for application to a product, a bag support 284 for holding bags in an upright orientation suitable for bagging the products, a bag sealer 286 for closing a plastic bag by heat, adhesive or the like, and a storage compartment 288 for temporarily storing bagged products. A push handle 290 enables a customer to push the stand from place to place, typically along aisles of a retail store.

0088FIG. 28 depicts a conventional, wire-frame shopping cart 292 equipped with the scanning arrangement incorporated in a hand-held head 294 that has a gun-shaped configuration. As best shown in FIG. 29, a snap-on holder 296, preferably constituted of a resilient plastic material, has walls bounding a compartment 298 in which a barrel of the gun-shaped head 294 is stored. The holder 296 has legs 300 which snap over and resiliently grip individual wires 302 of the wire-frame cart 292. A rubber-like, shock-absorbing pad 304 is mounted within the compartment 298 to protect the barrel of the head 294 from being nicked and damaged during withdrawal and replacement of the head relative to the holder.

0089As also shown in FIG. 28, the holder is mounted to the rear of the cart at one of the side walls, thereby avoiding damage to the holder and/or the head when multiple shopping carts are nested together. A fold-up display 306 is mounted at the front of the cart to display data concerning a product bearing a symbol being scanned.

0090Turning now to FIG. 30, a point-of-transaction counter 308, such as an appetizing counter, has a plurality of appetizing products such as fish 310, meat 312, potato salad 314, cheese 316, salami 318, just to mention a few exemplary choices. Each product is associated uniquely with a bar code symbol. For example, flags 320, 322, 324, 326, 328 bear unique coded symbols which, when electro-optically scanned, decoded and read, respectively identify the products 310, 312, 314, 316, 318.

0091The counter 308 also includes a cash register 330 of the type having a conventional cash drawer, a keyboard, a display, and a paper receipt tape assembly, together with an antenna 332 which is in radio frequency communication with an antenna 334 of a countertop scanner 336. A clerk stands behind the counter 308 and operates the scanner 336 and the cash register 330.

0092The scanner 336 is a modified version of the one depicted in FIG. 10, and includes a head 338 mounted at one end of a semi-rigid, bendable column 340 whose other end is connected to a base 342. The head 338 is equipped with a keyboard 344, a display 346 and a card reader having a slot 348 through which magnetically encoded customer cards, e.g. debit, credit or smart cards, are passed. The base 342 is equipped with a weighing scale 350, an elctronic surveillance tag deactivator 352, and a printer having an opening 354 through which paper tape and/or machine-readable and/or human-readable labels are passed. The scale has a weighing platform in the plane of the top wall of the base 342. The deactivator is mounted within the base and is operative to change the state of a tag associated with a product to deter theft. The printer is also mounted within the base, and ejects tape and/or labels for application to a product through opening 354.

0093In use, a customer walks up to the counter 308 and requests a portion of a particular product, such as salami 318. The clerk cuts and weighs the portion on scale 350 and aims the scanner 338 at the flag 328 to advise the system that the product being weighed is, in fact, salami. It is this optical identification of the product which prevents operator error as is common with manual entry of product identification codes in known systems.

0094With the product and its weight known, a local data base having price per unit weight information is interrogated, and a label is printed by printer 354. The label is applied to the salami portion, typically on a paper wrapping therefor.

0095During the weighing process, the clerk could check the display 346 to see that the correct product was identified, or could manually access the keyboard. After the label is applied to the product, a credit card can be passed through the reading slot 348 to charge the customer's account.

0096The scanner 338 need not be in wireless communication with the cash register 330, but could be hard wired thereto. Also, the scanner 338 need not be mechanically supported by the base 342, but could be mounted on a post or analogous support, fixed or manipulatable.

0097This invention is not intended to be limited to food counters, since any merchandise can be optically read in the manner described above. In a retail situation such as a clothing store, the tag deactivator 354 would be more useful.

0098FIG. 31 shows a gun-shaped head 360 detachably connected to a bendable arm 362, as previously described. One end of the arm 362 supports one part 364 of an electro-mechanical connector 366 whose mating part 368 is supported by the head 360. Thus, the head 360 can be removed for use as a hand-held head, or for purposes of repair and maintenance. The other end of the arm 362 is connected to a base 370 that rests on a support surface 372. The outgoing light beam is directed at a symbol placed underneath the head in the workstation mode, or at a symbol placed in front of the head in the hand-held mode.

0099FIG. 32 depicts another arrangement for accommodating right-handed and left-handed users, as previously discussed in connection with FIGs. 20 and 21. A laser/optics assembly 28, as previously described, is oscillated during scanning in the directions of the double-headed arrow 374. A light-directing element 376, preferably of light-transmissive material, is positioned in the light path of the light beam emanating from the assembly 28. The element 376 is positioned in either the solid-line or the dashed-line position, with the aid of a handle extending exteriorly of the housing 378. In the solid-line position, the element 376 steers the light beam about 10° - 15° off to the right of its straight-line path to accommodate left-handed users. In the dashed-line position, the element 376 steers the light beam about 10° - 15° off to the left of its straight-line path to accommodate right-handed users.

0100It will be understood that each of the elements described above, or two or more together, also may find a useful application in other types of constructions differing from the types described above.

0101While the invention has been illustrated and described as embodied in mirrorless scanners with movable laser, optical and sensor components, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

0102Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

0103What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

The invention may be summarized as follows:

0104<ul id="ul0002" list-style="none"><li>1. A scanner arrangement in a light scanning system for reading indicia having parts of different light reflectivity, comprising: <ul id="ul0003" list-style="none"><li>(A) a light source component for emitting a light beam;</li><li>(B) an optical component for optically modifying and directing the light beam along an optical path toward indicia located in the vicinity of a reference plane exteriorly of the system;</li><li>(C) a photodetector component having a field of view and operative for detecting at least a portion of light of variable intensity reflected off the indicia, and for generating an electrical signal indicative of the detected light intensity;</li><li>(D) a scanning component for scanning at least one of the light beam and the field of view;</li><li>(E) an electrical connecting component for conducting the electrical signal away from the photodetector component;</li><li>(F) all of said components being mounted together in a common assembly to constitute a compact, lightweight scan module; and</li><li>(G) means for mounting the scan module in an interchangeable, modular manner in housings of different configurations.</li></ul></li><li>2. The arrangement as recited in 1, wherein one of the housings is a hand-held terminal having a keyboard, a display and a rechargeable battery pack.</li><li>3. The arrangement as recited in 1, wherein one of the housings includes a read-control component for manually initiating scanning.</li><li>4. The arrangement as recited in 1, wherein one of the housings has a cylindrical shape and is sized to be held in a user's hand.</li><li>5. The arrangement as recited in 1, wherein the mounting means includes means for supporting one of the housings on a user's wrist.</li><li>6. The arrangement as recited in 5, wherein the supporting means includes a strap that at least partially encircles the user's wrist.</li><li>7. The arrangement as recited in 1, wherein the mounting means includes means for supporting one of the housings on the back of a user's hand.</li><li>8. The arrangement as recited in 7, wherein the supporting means includes a glove in which at least a part of said one housing is supported.</li><li>9. The arrangement as recited in 1, wherein the mounting means includes means for supporting one of the housings on a user's finger.</li><li>10. The arrangement as recited in 9, wherein the supporting means includes a ring that at least partially encircles the user's finger.</li><li>11. The arrangement as recited in 1, wherein the mounting means includes means for supporting one of the housings on a mobile cart.</li><li>12. The arrangement as recited in 11, wherein the cart is a shopping wagon having a support in which one of the housings is removably held.</li><li>13. The arrangement as recited in 11, wherein the cart includes a keyboard, a display, a scale and a printer.</li><li>14. The arrangement as recited in 11, wherein the cart includes a bag holder for holding a bag in an upright condition, and a bag sealer for sealing the bag.</li><li>15. The arrangement as recited in 1, wherein one of the housings is mounted at an end of a bendable arm for adjusting the position of said one housing relative to the indicia, said one housing including a keyboard, a display, and a card reader for reading encoded cards.</li><li>16. The arrangement as recited in 15, wherein said one housing includes a scale and a printer.</li><li>17. The arrangement as recited in 15, wherein said one housing includes a surveillance tag deactivator.</li><li>18. The arrangement as recited in 15, wherein the mounting means includes a detachable electro-mechanical connector having one part on said end of the arm, and a mating part on said one housing.</li><li>19. The arrangement as recited in 1; and further comprising means for converting one of the housings for use by a specific hand of a user, said converting means including means for steering the light beam to one of two courses.</li><li>20. A mounting method in a light scanning system for reading indicia having parts of different light reflectivity, comprising the steps of: <ul id="ul0004" list-style="none"><li>(A) emitting a light beam from a light source component;</li><li>(B) optically-modifying and directing the light beam by a light source component along an optical path toward indicia located in the vicinity of a reference plane exteriorly of the system;</li><li>(C) detecting at least a portion of light of variable intensity reflected off the indicia by a photodetector component having a field of view, and generating an electrical signal indicative of the detected light intensity;</li><li>(D) scanning at least one of the light beam and the field of view by a scanning component;</li><li>(E) conducting the electrical signal away from the photodetector component by an electrical connecting component;</li><li>(F) mounting all of said components together in a common assembly to constitute a compact, lightweight scan module; and</li><li>(G) mounting the scan module in an interchangeable, modular manner in housings of different configurations.</li></ul></li><li>21. A hands-free scanning system for reading indicia having parts of different light reflectivity, comprising: <ul id="ul0005" list-style="none"><li>(a) a housing having a window;</li><li>(b) actuatable electro-optical scanner means in the housing, for projecting a light beam through the window to indicia to be read, for scanning the indicia, and for detecting light of variable intensity that is reflected off the indicia to generate an electrical signal representative of the indicia;</li><li>(c) means for mounting the housing on an arm of an operator; and</li><li>(d) actuating means for actuating the scanner means to initiate reading of the indicia upon movement of the operator's hand relative to the arm.</li></ul></li><li>22. The system as recited in 21; and further comprising data entry means for manually entering data and display means for displaying information, said data entry means and display means being mounted on the housing to constitute, together with the scanner means, an integrated scanner and data terminal.</li><li>23. The system as recited in 21, wherein the window is located adjacent the operator's wrist, and wherein the scanner means projects the light beam over the back of the operator's hand in a pointing direction along which the operator's out-stretched forefinger generally points.</li><li>24. The system as recited in 21, wherein the actuating means includes a trigger switch switchable between switched states by flexure of the wrist of the operator's hand.</li><li>25. The system as recited in 24, wherein the switch includes a movable armature mounted on the housing.</li><li>26. The system as recited in 25, wherein the armature is pivotably mounted on the housing and overlies the back of the operator's hand.</li><li>27. The system as recited in 25, wherein the armature is an elongated handle pivotably mounted on, and laterally offset relative to, the housing, said handle extending between the forefinger and the thumb of the operator's hand.</li><li>28. A method of reading indicia having parts of different light reflectivity, comprising the steps of: <ul id="ul0006" list-style="none"><li>(a) mounting an actuatable electro-optical scanner having a window on an arm of an operator; and</li><li>(b) actuating the scanner by moving the operator's hand relative to the arm to project a light beam through the window to indicia to be read, to scan the indicia, and to detect light of variable intensity that is reflected off the indicia for generating an electrical signal representative of the indicia.</li></ul></li><li>29. The method as recited in 28, wherein the actuating step is performed by pointing the operator's outstretched forefinger toward the indicia, and by tracing the forefinger in free space across the indicia while simultaneously flexing the operator's wrist.</li><li>30. The method as recited in 28, wherein the actuating step is performed by overlying an armature of a trigger switch over the back of the operator's hand.</li><li>31. The method as recited in 28, wherein the actuating step is performed by extending an armature of a trigger switch between the forefinger and the thumb of the operator's hand.</li></ul>