CN103026366B - Data Reader with Compact Arrangement - Google Patents

Abstract

The present invention relates to a data reader (10, 100, 150, 300) comprising one or more imagers or imager assemblies (50, 126/128, 177/178, 350) acquiring two-dimensional images of an object placed in a viewing volume (5), the data reader having fold mirrors (60/62, 122/124, 172/174/176, 362/360) and other component arrangements allowing for a compact and efficient component configuration.

Description

Data Reader with Compact Arrangement

technical field

The field of the present disclosure relates generally to imaging, particularly but not exclusively to the reading of optical codes such as barcodes for example.

Background technique

The optical code encodes useful, optically readable information about the item to which it is attached or otherwise associated. Perhaps the best example of an optical code is a barcode. Barcodes are ubiquitous on, or associated with, various types of objects such as retail packaging (e.g., UPC codes), wholesale and stocked goods; retail product display fixtures (e.g., shelves); items in manufacture ; personal or business property; documents; and documentation files. By encoding information, barcodes are often used as identifiers of objects, where the identification is a class of objects (for example, a milk container) or a unique item.

A barcode includes alternating bars (ie, relatively dark areas) and spaces (ie, relatively light areas). The pattern of alternating bars and spaces and the width of these alternating bars and spaces represent strings of binary ones and zeros, where the width of any particular bar or space is an integer multiple of a prescribed minimum width, which is called a "module" or " unit". Therefore, in order to encode information, a barcode reader must be able to reliably discern the pattern of bars or spaces, for example by determining the position of the border demarcation line between adjacent bars and spaces that spans the entire length of the barcode.

Barcodes are just one example of the many types of optical codes currently in use. The most commonly used barcodes are one-dimensional or linear optical codes, such as UPC or Code 39 barcodes, where information is encoded in one direction—perpendicular to the direction of the bars and spaces. Higher dimensional optical codes, sometimes called "barcodes", such as 2D matrix codes (eg, MaxiCode) or stacked codes (eg, PDF417) are also used for various purposes.

Imager-based readers use a camera or imager to generate electronic image data (often displayed digitally) of an optical code. Next, the image data is processed in order to find and decode the optical code. For example, virtual scan line technology is a known technique for digitally processing an image containing an optical code by searching the image along multiple lines, usually spaced apart and at various angles, somewhat similar to laser-based scanners The scan pattern of the laser beam.

Imager-based data readers are often only capable of forming images from one perspective of a normal vector outside the face of the imager. Imager-based readers can utilize ambient light or they can include light sources such as LEDs to acquire images. When the label is oriented such that light from the illumination source is reflected directly back into the imager, the imager may not read it correctly due to uniform reflections that completely wash out the desired image, or due to reflections from textured specular surfaces that wash out one or more features, The imager may not be reading correctly. This effect can cause problems reading glossy labels at certain reflection angles, and labels positioned at extremely acute angles relative to the imager may be unreadable. Also, outgoing illumination light tends to reflect undesirably from the back and front sides of the window and back onto the imager. In the case of a fixed scanner, the viewing size of the scanner nose needs to be large, usually 50nm to 100nm, which means that the distance from the imager to the scanner nose needs to be long, for some scanners, at 70nm to the 120nm class. These and other physical and functional constraints make it difficult to achieve a compact arrangement of data reader components (ie, window, printed circuit board (PCB), internal mirror, and imager).

Accordingly, the present inventors have determined that it would be desirable to provide an imager-based reader that improves upon the limitations of existing imager-based readers.

Contents of the invention

Description of drawings

Figure 1 shows a schematic side view of a display-type data reader according to a preferred configuration and showing internal components.

FIG. 2 shows a schematic front plan view of the data reader of FIG. 1 .

FIG. 3 shows a schematic front plan view of the data reader of FIG. 2 without the housing and with a spare condenser lens, taken along line 3-3.

Figure 4 shows a bottom rear isometric view of the data reader of Figures 1-3.

FIG. 5 shows a front left isometric view of the data reader of FIG. 3 .

Figure 6 shows a schematic side view of an imager-type data reader according to a first alternative configuration.

Figure 7 shows a schematic side view of an imager-type data reader according to a second alternative configuration.

Figure 8 shows a schematic side view of an imager-type data reader according to a third alternative configuration.

Figure 9 shows a schematic view of a conventional mirror mounting arrangement in a data reader.

Figure 10 shows a schematic view of a preferred embodiment for a mirror mount arrangement in a data reader.

Figure 11 shows a schematic view of an alternate embodiment for a mirror mount configuration in a data reader.

Figure 12 shows a schematic front plan view of a demonstration scanner with a single PCB layout and a central opening in the PCB.

Figure 13 shows a schematic side view of a display scanner with slanted windows and deep grooves.

Figure 14 shows a schematic side view of a data reader according to another alternative embodiment.

FIG. 15 shows a front elevational view of the data reader of FIG. 14 .

Figure 16 is a cross-sectional view of the data reader of Figure 15 taken along line 16-16.

Figure 17 shows an exploded view of the internal components of the data reader of Figures 4-16.

Figure 18 shows an exploded view of the internal components of Figure 17 partially assembled.

Figure 19 shows an isometric view of the internal components of Figure 17 fully assembled.

detailed description

With reference to the foregoing drawings, this section describes certain embodiments and their detailed construction and operation. The embodiments described herein are set forth by way of example only, and not limitation. In light of the teachings herein, it should be recognized that there is a range of equivalents to the example embodiments described herein. Most obviously, other embodiments are possible, changes may be made to the embodiments described herein, and there may be equivalents to components, parts or steps making up the described embodiments.

For simplicity and clarity, certain aspects of components or steps of certain embodiments are not shown in unnecessary detail, such details would be apparent to those skilled in the art in light of the teachings herein, and/or such Details can obscure understanding of more relevant aspects of the embodiments.

1-5 show a data reader 10 according to a first preferred embodiment. FIG. 1 shows in particular a reader 10 with a housing 20 having an upper part 22 pivotally attached to a base part 23 . The connection between the upper housing part 22 and the base part 23 preferably includes a pivot mechanism 24 as described below, which allows the upper housing part 22 to tilt relative to the base part 23 . Reader 10 includes a front window 64 on its front/front. As shown in FIG. 1 , the reader 10 is set in an inclined position such that the window 64 is oriented generally vertically and faces generally sideways, as such for reading barcodes on the vertical side of the item/item. The reader 10 can be tilted downward so that the window 64 is oriented in a diagonally downward facing direction suitable for reading a barcode on top of an item, or can be tilted upward so that the window 64 is oriented in a direction suitable for reading a barcode on the bottom of an item. The diagonal upward facing direction of the barcode.

The reader 10 is shown having a curved upper housing 22 that accommodates grip in the user's hand. An optional starter or actuation button 25 may be provided at a suitable/convenient location on the housing 22 ; alternatively, the starter or actuation button 25 may be provided on the base member 23 . Alternatively, housing 22 may be of other configurations such as a box shape. The compactness of the internal components and housing enables the unit to be lifted and operated in handheld mode.

The reader 10 may be linked to the host via a cable 30, or it may be linked via a wireless connection such as RF (eg Bluetooth, Zigbee), IR (infrared) or microwave. Alternatively, the cable 30 may be connected to the base part 23, particularly suitable for embodiments where the base part 23 remains attached to the upper housing 22 in a handheld mode.

Reader 10 includes one or more circuit boards (PCBs), such as PCB 40 mounted within upper housing part 22 . The main PCB 40 has a planar profile and is preferably oriented at approximately an acute angle to the front window 64 , mounted toward or mounted on the rear side of the housing member 22 . The acute angle is preferably between 30° and 60° or on the order of 45°. Electronics mounted on PCB 40 include RJ-45 connector 34, microprocessor 42 and any memory, imager assembly 50 (composed of lens 52, two-dimensional sensor array 53, and aperture 54), illumination system 70 (composed of LED72 and reflector cone 74). Also mounted within the housing part 22 are a first mirror 62 mounted on the PCB 40 via a bracket 63 and a second mirror 60 mounted on the housing part 22 via a bracket 61 . A two-dimensional image of an object 90 in the viewing volume 5 is acquired and propagated from one perspective, and reflected down by the primary mirror 62 through the window 64 along the first image path segment 80 , along the second image path segment 82 Reaching the second mirror 60 , the second mirror 60 reflects the image up and/or sideways along a third image path segment 84 to the imager assembly 50 which may be supported by the PCB 40 . The image may be focused by a suitable focusing lens 52 and aperture 54 positioned in front of an imaging array 53 that acquires a two-dimensional image of object 90 . Primary mirror 62 is oriented at an acute angle relative to window 64 . The acute angle is preferably between 30° and 60° or on the order of 45°.

For descriptive purposes, this document uses a naming convention where the primary mirror is the first reflective surface of the object image, the secondary mirror is the second reflective surface, and the tertiary mirror is the third reflective surface, etc., so that the image of the object is reflected from the primary mirror To the secondary mirror, then to the third mirror. Thus in the reader 10, the first mirror 62 may be referred to as the primary mirror, and the second mirror 60 may be referred to as the secondary mirror, wherein the image of the object 90 in the viewing volume 5 passes through the window 64 and is captured by the primary mirror. Mirror 62 reflects to secondary mirror 60, then to imager assembly 50, which then takes/captures a two-dimensional image of object 90 and converts the image into an electronic signal format for processing/encoding.

The primary mirror 62 mounted on the PCB 40 via a mounting bracket 63 is arranged at a relatively small acute angle relative to the PCB 40, for example on the order of 10-15° or less. 1 shows an example where mirror 62 is oriented at an angle of about 60° relative to front window 64 and about 12° relative to PCB 40; FIG. ° angle or parallel to PCB40 for example. Alternatively, the mirror 62 may be mounted/attached directly to the surface of the PCB 40 by a suitable attachment mechanism, such as via screws, double-sided tape or adhesive.

The pivot mechanism 24 comprises a circular male part 26 which nests into a corresponding cylindrical cavity part 28 of the base part 23 . Male cylindrical member 26 is secured within cylindrical cavity member 28 via a suitable attachment mechanism, such as a pin and sleeve combination. Other suitable attachment mechanisms may be used. For example, a magnetic coupling mechanism can secure the cylindrical part to the cavity part, the magnetic force maintaining the connection between the parts also allows for pivoting or even separation. In another arrangement, the lower part 26 may comprise a spherical part that nests into the cavity part 28, the ball snap-fitting in the cavity and held in place by a friction fit, also allowing pivoting or even separation.

Illumination system 70 is shown mounted in the upper region of the housing with three groups of three LEDs 72a, 72b, 72c (LEDs 72a-c mounted on PCB 40), each group of LEDs being arranged in a respective reflective array 74a , 74b, 74c, which are operable to direct the field of view of the LED illumination along a desired outward pathway. The reflective array or reflective cone 74a (to the right of the reader 10 as viewed in FIG. 2 ) is formed as a cone with four reflective inner surfaces operable to reflect and direct light from the three LEDs 72a disposed at the bottom of the cone. Light. Similarly, reflective array or reflective cone 74a (on the left side of reader 10 as viewed in FIG. 2) is formed as a cone with four reflective inner surfaces operable to reflect and guide The light of LED72b. A third reflective array 74c in which three LEDs 72c are disposed is disposed between the reflective arrays 70a and 70b. The third reflective array 74c may have a tapered shape with four reflective surfaces, but is shown with the lower reflective surface removed. LEDs 72 may be oriented to direct light at a small downward angle (approximately 10° to 15°) from perpendicular to window 64 so that less light is aimed directly at the user, with the result that too bright light is not displayed to the user.

Reader 10 also includes a speaker 36 . in this configuration. Speaker 36 is disposed near the front surface of housing 22 and is connected to PCB 40 via a wired connection.

PCB 40 is mounted close to the rear wall of housing part 22 and is oriented at an acute angle of the order of 30° relative to front window 64 such that imager 50 disposed on PCB 40 does not face window 64 directly. Thus, outgoing light from the camera system 70 that is reflected back from the window 64 is less likely to be reflected at an angle/direction so as to travel along a direct path of incidence to the imager. Further, by having the primary mirror 62 set at an acute angle (e.g., on the order of 45°) relative to the window 64, outgoing light from the camera system 70 reflected back from the window 64 is less likely to travel along the The angle/direction of the direct incident path 82, 84 going forward is reflected.

The combination of the orientation of the primary mirror 62 relative to the window 64 and the orientation of the PCB 40 relative to the window 64 can achieve certain advantages, such as one or more of the following:

- compact configuration of the reader assembly within the housing 22 with a large window reading area;

- enables both the imager 50 and the lighting LED 72 to be mounted on a common PCB 40;

-- (via mirrors 62 , 60 ) reflect incident light path through window directly to imager 50 without passage through central opening of PCB 40 .

- The arrangement of the front window 64, primary mirror 62 and PCB 40 allows the reader 10 to be constructed with only a single PCB (PCB 40 including the lighting electronics, imager 54 and other parts) while maintaining the relatively large size of the window 64 Viewing size and close vertical arrangement between viewing direction 80 and window 64 . Thus, the arrangement of components in the reader 10 can be compared favorably to the reader 250 shown in FIG. 250 may include a plurality of plates) and a plurality of illumination LEDs 258 disposed at one end of the plate 252 . The arrangement of components in the reader 10 can also be compared favorably to the reader 275 shown in FIG. Deep mechanically recessed area 278 behind end 279. Figure 13 further shows an imager 280 mounted on a PCB 282 having a field of view or image path 290 focused by a lens 286, the imager 280 acquires/captures a two dimensional image of the object/target. The field of view is illuminated by illumination LEDs 288 , 289 mounted on PCB 284 .

Reader 10 is shown as a vertically oriented reader, i.e. window 64 is oriented generally vertically, but a pivot mechanism can be used to adjust the orientation of the unit to be oriented in a diagonally downward position or diagonally upward. Inclined position.

6 and 7 show similarly configured optical readers 100 and 150 according to the first and second alternative embodiments. The reader 100 of FIG. 6 includes a housing 110 with a front, vertically oriented window 120 . The image of the scanned area field of view passes through the window 120, along a first image path segment 130 where the image is reflected downward by the primary mirror 122, along a second image path segment 132 to the secondary mirror 124 where the image is reflected sideways and backwards, A third image path segment 134 is followed to an imager assembly including a lens system 126 and a detector array 128 that acquires/captures a two-dimensional image of the object. The sensor array 128 may be supported by a PCB disposed on the rear wall of the housing 110 in a similar configuration as the reader 10 of FIG. 1 . Primary mirror 122 is oriented at an acute angle relative to window 120 . The acute angle is preferably between 30° and 60° or on the order of 45°.

The reader 150 of FIG. 7 includes a housing 160 with a front, vertically oriented window 170 . The image of the field of view of the scan area passes through window 170, along a first image path segment 180 where the image is reflected downwards by primary mirror 172, and along a second image path segment 182 to a secondary mirror where the image is reflected sideways and backwards and slightly upwards 174, along the third image path segment 186 to the third mirror 176 that reflects the image downward, and along the fourth path segment 186 to the imager assembly including the lens system 177 and the detector array 178 that acquires the two-dimensional image of the object. Sensor array 178 may be supported by a PCB disposed on the bottom wall of housing 160 in a similar configuration as reader 10 of FIG. 1 . Primary mirror 172 is oriented at an acute angle relative to window 170 . The acute angle is preferably between 30° and 60° or on the order of 45°.

The two-mirror system (primary mirror 122 and secondary mirror 124) of reader 100, which has a shorter internal path than the three-mirror system of reader 150, requires greater housing depth in order to achieve the same field of view as reader 150 and depth of field.

FIG. 8 shows another alternative reader 200 . Reader 200 has a three-bounce mirror configuration. Reader 200 includes a housing with a vertically oriented window 220 . The image of the scanned field of view passes through window 220, along a first image path segment 230 where the image is reflected upwards by primary mirror 222, along a second image path segment 232 to secondary mirror 224 where the image is reflected sideways and backwards and slightly upwards , along the third image path segment 234 to the third mirror 226 that reflects the image back, and along the fourth path segment 236 to the imager assembly including the lens system 227 and the detector array 228 . The mirror edge is preferably positioned close to the scanning volume in order to minimize reader depth. The sensor array 228 acquires a 2D image of the target/object and it may be supported by a PCB disposed on the rear wall of the housing 110 in a similar structure like the reader 10 of FIG. 1 . Unlike the previous embodiment, off-axis light 290 reflected from primary mirror 222 may reflect back from window 200 and return along path 294 of mirrors 222 , 224 , and 226 , undesirably reaching sensor array 228 .

To achieve the desired scan area of the window, a suitable optical path length is 130mm. Using the three bounce mirror configuration of the reader 200, the minimum depth of the reader can be less than 60nm. A two bounce mirror configuration of reader 150 would require more depth. But a single bounce mirror configuration would require a tall reader.

14-19 illustrate another embodiment of a data reader 300 . 14-16 show in particular a reader 300 with a housing 310 having an upper part 312 pivotally attached to a base or stand part 313 . The connection between the upper housing part 312 and the base part 313 preferably includes a pivot mechanism 314 which allows tilting of the upper housing part 312 relative to the base part 313 . Reader 300 includes a front window 364 (removed in FIGS. 14-15 but shown in FIG. 16 ) on the front of upper housing member 312 . In FIGS. 14-16 , reader 300 is shown in an angled position such that window 364 is oriented generally vertically and facing generally sideways, as such for reading barcodes on the vertical side of an item. The reader 300 can be pivoted and tilted downward so that the window 364 is oriented in a diagonally downward facing direction suitable for reading a barcode on top of an item, or can be pivoted/tilted upward so that the window 364 is oriented in a direction suitable for reading a barcode on top of an item. Take the diagonally upward facing direction of the barcode on the bottom of the item.

Reader 300 may have a generally curved upper housing 312 that accommodates grasping by a user's hand. An optional starter or actuation button 315 may be provided at a suitable/convenient location on the housing 312 ; alternatively, the starter or actuation button 315 may be provided on the base member 313 . Other actuation mechanisms such as those disclosed in US Application 13/117563 or US Patent 7,243,850 are incorporated herein by reference. Alternatively, housing 312 may be other structures, such as a box with one or more windows, or other configurations, such as the data reader disclosed in US Patent No. 7,243,850.

The reader 300 may be linked to the host via a cable 330 at the upper housing part 312 connected by a suitable connector (e.g., RJ-44 connector), or it may be linked via, for example, RF (e.g., Bluetooth, Zigbee), IR or microwave wireless connection is linked. Alternatively, the cable 330 may be connected to the base member 313, particularly suitable for embodiments where the base member 313 remains attached to the upper housing 312 in a handheld mode.

Reader 300 includes one or more printed circuit boards (PCBs), such as PCB 340 mounted within housing component 312 . The main PCB 340 has a planar profile and is preferably mounted towards the rear of the housing member 322 or at the rear of the housing member 22 , oriented at approximately an acute angle to the front window 364 . The acute angle is preferably between 30° and 60° or on the order of 45°. Electronics mounted to PCB 340 include imager assembly 350 (consisting of lens, sensor array 353 and aperture); microprocessor 342 (and other electronics such as memory, communication chipset, analog to digital converter, etc.) ; three sets of LEDs 372a, 372b, 372c; speaker 336 and RJ-45 connector 334. Connector 334 receives an RJ-45 plug 331 at the end of cable 330 .

Reader 300 is functionally/optically similar to reader 10 , but includes a sub-housing or optical housing 390 . The first mirror 362 and the second mirror 360 are mounted in an optical chassis 390 that mounts and/or arranges various optical components. The optical housing 390 is preferably constructed of molded optical plastic or other suitable structure that provides a relatively high precision structure that, when attached/mounted to the PCB 340, provides the first and second mirrors 362, 360 and the bearings on the PCB 340. Precise alignment/arrangement of imager 350 and reflector array 370 of LEDs 372a-c within the housing.

As can be seen from the cross-sectional view of Figure 16, an image of object 90 in viewing volume 5 is acquired from a perspective and propagated as follows: (1) along first image path 380, through window 364, then to main Mirror 362, (2) the primary mirror 362 reflects the image downward along the second image path segment 382 to the secondary mirror 360, (3) the secondary mirror 360 reflects the image upward and/or sideways, and reaches along the third image path segment 384 Imager assembly 350, (4) The imager assembly acquires two-dimensional images via imaging array 353 and converts the acquired images into electronic form for processing/decoding. The imager assembly in this example is mounted on/supported by PCB 340 . The image may be focused by a suitable focusing lens and aperture (similar to lens 52 and aperture 54 of FIG. 3 ) located in front of imaging array 353 . Primary mirror 362 is oriented at an acute angle relative to window 364 . The acute angle in one example is chosen between 30° and 60°, especially on the order of 45°.

For descriptive purposes and convenience, the naming conventions listed above with respect to reader 10 of FIG. .

17-19 illustrate assembly schemes for various internal components of reader 300 . FIG. 17 shows the three main internal components, namely optical housing 390 , illumination reflector assembly 370 , and PCB 340 , in an exploded view. Reflector assembly 370 is constructed of a suitable material, such as molded optical plastic, and includes three emitter arrays 374a, 374b, 374c, upper mounting pins 377a, 377b, and lower brackets 376a, 376b. The reflector assembly 370 is attached to the PCB 340 by: (1) setting the mounting pins 377a, 377b into the PCB corner cutouts or slots 341a, 341b; (2) aligning the openings of the lower brackets 376a, 376b with the PCB holes 403b, 403c Align; and (3) Insert screws 404b, 404c into holes 403b, 403c and through openings of lower brackets 376a, 376b. As shown in FIG. 18, once the reflector assembly 370 is mounted in place on the PCB 340, the reflector arrays 374a, 374b, 374c are aligned with and surround the corresponding LED arrays 372a, 372b, 372c. . As shown in FIG. 16 , post 377 b has cutouts that slide over/around PCB 340 to provide a secure connection to the top of reflector assembly 370 .

In one example construction, optical housing 390 is molded as a single piece by a suitable molding process, such as injection molding. Similarly, emitter assembly 370 may also be molded as a single piece by a suitable molding process, such as injection molding.

Optical housing 390 includes a first mounting surface or frame 391 on which primary mirror 362 is mounted, and a second mounting surface 393 on which secondary mirror 360 is mounted. Optical rack 390 is mounted to PCB 340 via a suitable number of leg brackets (in this example four leg brackets 394a, 394b, 394c, 394d are used). The reflector assembly 370 is attached to the PCB 340 by (1) aligning the leg brackets 394a, 394b, 394c, 394d with the corresponding PCB holes 403a, 403b, 403c, 403d; (2) aligning the screws 404a, 404b, 404c, 404d are inserted into holes 403a, 403b, 403c, 403d (screws 404b, 404c also pass through openings of lower brackets 376a, 376b), and into leg brackets 394a, 394b, 394c, 394d. Leg brackets 394 a , 394 b , 394 c , 394 d have hollow interiors with female threads into which screws can be secured to secure/mount optical housing 390 to PCB 340 .

The construction is also simplified by the location where the speaker 336 is mounted on the PCB 340 . Optical housing 390 includes a hollow cylinder 396 with an elliptical outer opening 392 . A shroud 337 made of stretchable rubber or plastic is inserted over and around the rear end of the cylinder 396 (see Figures 17-18) and then when the optical housing 390 is positioned on the PCB 340 (see Figures 14-16) , the cylinder 396 is aligned with the speaker 336, and the cover 337 is inserted over and around the speaker 336. The enclosure provides an air or acoustic seal between speaker 336 and cylinder 396 . Thus, the sound from the speaker 336 is transmitted through the cylinder out of the oval opening 392 . Opening 392 may be oval, circular, square, or any suitable shape. As an aid for aligning the cover 337 on the cylinder 396 , the optics chassis 390 includes an alignment post 397 relative to one side of the cylinder 396 . The cover 337 includes a corresponding flange 338 with holes. When assembled, the shroud 337 is positioned and slides onto the cylinder 396 and the flange slides onto the alignment post 397 .

Mounted and aligned on PCB 340 via optics mount 390, primary mirror 362 is positioned at a relatively small acute angle relative to PCB 340, for example on the order of 10-15° or less. FIG. 16 shows mirror 362 oriented at an angle of approximately 60° relative to front window 364 and approximately 12° relative to PCB 340 . Alternatively, optical housing 390 may be configured to arrange mirrors 362, 360 at other suitable angles, such as the angle of mirrors 62, 64 in FIG. 3 above.

The lighting system is shown with LED groups 372a, 372b, 372c mounted in the upper region of the housing, with each LED group having three LEDs. LED groups 372a-c are mounted on PCB 340, with each LED group disposed within a respective reflector array 374a, 374b, 374c operable to direct the field of view illuminated by the LEDs along a desired outward path . A reflective array or reflective cone 374a (to the right of the reader 300 as viewed in FIG. 15 ) is formed as a cone with four reflective inner surfaces operable to reflect and direct light from the three LEDs 372a disposed at the bottom of the cone. Light. Similarly, reflective array or reflective cone 374b (on the left side of reader 300 as viewed in FIG. 15 ) is formed as a cone with four reflective inner surfaces operable to reflect and direct light from three The light of a LED372b. A third reflective array 374c in which three LEDs 372c are disposed is disposed between the reflective arrays 370a and 370b. The third reflective array 374c may have a tapered shape with four reflective surfaces, but is shown with the lower reflective surface removed. LED 372c may be oriented to direct light at a small downward angle (approximately 10° to 15°) from perpendicular to window 364 so that less light is directed at the user and as a result does not appear too bright to the user.

For descriptive purposes, reader 10 of FIG. 1 is shown with viewing path 80 (shown in phantom) that includes viewing volume 5 in front of reader window 64 . Similarly, reader 300 in FIG. 16 is shown with viewing path 380 (shown in dashed lines) enclosing viewing volume 5 in front of reader window 364 . In these examples, the viewing volume may be referred to as a scanning volume or scanning region, which is a volume of 3D space where there is a high probability of successfully reading an optical code disposed within the volume of space. It should be understood that the viewing volume shown in the figures is not an exact representation of the area of the volume that is viewable through the window through which a reader can read an object placed in the window. The viewing volume is typically defined by the window 64 (or window 364 ) and the maximum distance extending outward within the reader's depth of field. Viewing volumes in other figures may be shown and described in a similar manner. It should also be appreciated that in reader 10 of FIG. A viewing volume 80 is defined in the lower portion of the window 64 . Alternatively, the front window may be bisected into separate windows, one window for the light path of the illumination system 70 and one window for the image path 80 . The components of reader 300 may be similarly described.

The mirror assembly is preferably high quality reflective optics and may be formed by a suitable process, for example by monolithic or substrate (eg metal or plastic) followed by application of a reflective coating.

Reader 10 and reader 300 are shown with three LED arrays for illumination, but fewer or more arrays may be used. Although not shown, reader 100 of FIG. 6 and reader 150 of FIG. 7 may provide a similar lighting system. In some embodiments, different wavelengths of light can be directed to illuminate different regions of an object from different perspectives. In some embodiments, one or more light sources may be operated in a pulsed mode, the pulses being synchronized to the frame rate of the imager. In one example, the imager may select a frame rate of 30 Hz, illuminate the read zone with one or more light sources and pulse at 60 Hz. An example of light source pulses is in US Patent No. 7,234,641, which is hereby incorporated by reference.

Also, while the configurations of reader 10 shown in FIG. 1 and reader 300 shown in FIG. 14 have a single planar PCB 40/34, other configurations may be implemented. For example, a PCB can be non-planar. Alternatively, the reader may comprise multiple PCBs. In one example of a two PCB configuration, the reader includes (1) a first PCB including the imager and microprocessor, on which is mounted a first mirror or optics housing; and (2) a second PCB with illuminating LEDs. Two PCBs, on which the lighting reflector is mounted.

In addition to the previously stated variations and combinations, various embodiments may advantageously employ the lenses and shutters, other arrangements, and/or image acquisition techniques disclosed in US Patent Publication No. 2007/0297021.

In another aspect, FIG. 10 illustrates a mirror mounting configuration for a mirror within a reader, such as reader 10 of FIG. 1 or such as reader 300 of FIG. 14 . As generally shown in FIG. 9 , the mirror 202 is mounted within the scanner housing via double-sided tape 204 on the rear surface of the mirror 202 and on a mounting surface 200 , such as a rear wall. According to the structure shown in FIG. 10 , it provides a mirror basket or housing wall 210 with an opening 212 behind which a mirror 215 is positioned and secured by a double-sided adhesive tape 214 between the top surface of the mirror 215 and the wall 210 . fixed. Alternatively, mirror 215 may be secured to wall 210 via adhesive, via clips, or some other suitable attachment/fixation mechanism. For example, Figure 11 shows an alternative attachment mechanism in which wall 210 includes an outer lip 211 and mirror 215 is secured to lip 211 by clips 220, 222 and a strip of compressed foam 214 disposed therebetween.

In contrast to the conventional configuration shown in FIG. 9 , the edge of the mirror 215 is not visible (hidden behind the basket opening 212 ), and the mirror's visible reflective area is defined by the size of the opening 212 . The visible reflective area of mirror 215 can be considered to be framed by wall opening 212 . Also, since the reflective area is defined by the size of the opening 212 rather than the size of the mirror 215, the tolerance requirements for the mirror 215 are relaxed.

A fixed virtual scan line pattern, preferably an omnidirectional pattern, can be used to decode the image, such as that used in the Magellan-1000i scanner manufactured by Datalogic Scanning, Inc., Eugene, Oregon. In some embodiments, alternative techniques may be employed, such as (a) vision library-based processing may be used for one or more imagers; (b) processing based on a hybrid of virtual scanline patterns and vision libraries, For example calling the vision library every n frames.

To reduce the amount of memory and the processing required to decode linear and stacked barcodes, suitable virtual scanline processing methods can be employed. VSL is a linear subset of two-dimensional images arranged at various angles and offsets. These virtual scan lines can be processed as a set of linear signals in a manner conceptually similar to flying-spot scanning for laser scanners. Images can be sharpened using a 1D filter kernel instead of a full 2D kernel, thereby significantly reducing processing requirements.

The rotationally symmetric nature of the lens blur function allows a linear sharpening process to occur without requiring any pixels outside the bounds of the virtual scan line. The virtual scan lines are assumed to be approximately orthogonal to the bars. The bars absorb the blurry speckle modulation in the non-scanned axis, resulting in a line spread function in the scanned axis. The resulting line spread function is the same regardless of the virtual scan line positioning. However, since the pixel pitch changes according to rotation (a 45 degree virtual scanline has a pixel pitch that is 1.4X larger than a horizontal or vertical scanline), the scaling of the sharpening equalizer needs to change with the angle.

If an imager captures an image of a stacked barcode symbol, such as a data bar or a PDF-417 code, the imaging device can start an omnidirectional virtual scanline mode (such as omnidirectional mode) and then determine which scanline is most aligned with the barcode. The pattern can then be adapted for the next or subsequent frame to more closely align with the orientation and position of the barcode, such as a pattern of closely spaced parallel lines. As a result, devices can read truncated and stacked barcodes using less processing than a reader that processes the entire image in each frame.

Through a process called stitching, incomplete parts of an optical code (from multiple perspectives) can be combined to form a complete optical code. While splicing is described herein by way of example to UPCA labels, one of the most commonly used types of optical codes, it should be understood that splicing can be applied to other optical label types. UPCA labels have "Guard Strips" on the left and right sides of the label, and a center guard graphic in the middle. Each side has 6 numbers encoded. It is possible to tell whether the left half and the right half are decoded. It is possible to decode the left and right halves separately, and then merge or concatenate the decoded results together to produce a complete label. It is also possible to splice the label from two pieces to one side. To reduce errors, these incomplete scans are required to include some overlapping regions. For example, denoting the end guard pattern as a G, and the center guard pattern as a C, and then encoding the UPCA label 012345678905, the label could be written as G012345C678905G.

Splicing the left and right halves brings the readings G012345C and C678905G, putting them together to get the complete label. Splicing of the left half where the 2 digits overlap can bring reads G0123 and 2345C in order to arrive at G012345C. An example virtual scanline decoding system can output label sheets as short as a guard pattern and 4 digits. Using stitching rules, complete labels can be assembled from slices decoded from the same or subsequent images from the same camera, or from slices decoded from images from multiple cameras. Further details of stitching and virtual line scanning methods are described in US Patent Nos. 5,493,108 and 5,446,271, which are hereby incorporated by reference.

In some embodiments, the data reader includes an image sensor or array that is progressively exposed to acquire rolling-based images, such as a CMOS imager and rolling shutter. Image sensors use processors to detect and quantify ambient light levels. Based on the intensity of the ambient light, the processor controls the integration time of the row of CMOS imager photodiodes. The processor can also coordinate when to pulse the light source based on the intensity of the ambient light and the integration time of the photodiode row.

Depending on the amount of ambient light and integration time, the light source may be pulsed one or more times per frame to produce a stop motion image of the moving object suitable for processing to decode data represented by the moving object. In bright ambient light conditions, for example, the processor can cause the rows to be integrated successively with relatively short integration times without a pulsating light source, which produces oblique images of moving objects. In moderate light conditions, e.g. rows can be integrated successively with an integration time similar to the integration time for bright ambient light, the processor pulses the light source several times per frame in order to produce stop motion for moving objects with multiple offsets between image parts image. Image parts are produced when pulses of light can overlay a blurred, tilted image of a moving object. In low ambient light conditions, for example, the processor may cause the rows to integrate successively with relatively long integration times, and the light source may be pulsed once during the same period of time when all rows are integrating. A single pulse of light produces a stop-motion image of a moving target that can overlay a blurry, tilted image of the moving target.

In some embodiments, the data imager includes multiple CMOS imagers and has multiple light sources. Different CMOS imagers "see" different light sources, in other words, light from different light sources is detected by different CMOS imagers. When the CMOS imagers operate at relatively similar frame rates, relatively synchronized images can be acquired by multiple CMOS imagers without synchronizing the CMOS imagers. For example, one CMOS imager is used as the main imager so that all light sources are pulsed while several rows of main CMOS imagers are integrating.

Another embodiment pulses the light source more than once per frame. Preferably, the light source is pulsed over several lines of integration, and the number of integrated lines is less than the total number of lines in the CMOS imager. In some embodiments, the result of dividing the total number of rows in the CMOS imager by the number of integrating rows is an integer. Alternatively, in other embodiments the result of dividing the total number of rows in the CMOS imager by the number of integrating rows is not an integer. When the result of dividing the total number of rows by the number of integrating rows in the CMOS imager is an integer, the image frame can be divided into equal segments for each frame. On the other hand, when the result of dividing the total number of rows by the number of integrating rows in a CMOS imager is not an integer, consecutive image frames can be divided into different segments.

Other embodiments may use a mechanical shutter instead of a rolling shutter in order to acquire stop motion images of moving objects. The mechanical shutter may include a flexible member attached to the shutter that blocks light in close contact with the CMOS or other suitable image sensor. The shutter may be attached to a spool having conductive material wrapped around a spool portion of the spool that faces away from the shutter. The spool portion of the spool may be approximately one or more permanent magnets. When an electric current is run through a conductive material wound on a spool, a magnetic field is created, and the magnetic fields of one or more permanent magnets interact to move the shutter into a position that allows light to come into close contact with the CMOS or other suitable image sensor.

These and other improved imaging techniques are described in detail in US Published Patent Application No. 2010/0165160, entitled "Systems and Methods For Imaging," which is incorporated herein by reference.

Readers 10, 100, and 150 are shown as single window readers with vertically oriented windows, but they could be incorporated into other configurations, like for example in-counter/horizontal readers facing upwards. In another configuration, multiple reader modules may be provided in a multi-window reader that provides reading viewing volumes from different directions/perspectives.

Although primarily described with respect to a checker-assisted data reader, the readers and methods described herein may be used in self-checkout systems. The optical readers described herein can be used in automated readers such as tunnel scanners employing multi-reader modules that obtain multiple perspectives through multiple viewing windows.

Obviously, parts of the subject matter disclosed herein may be combined with one or more other parts of the subject matter disclosed herein, as long as such combination is not mutually exclusive or inoperable.

The terms and descriptions used above are set forth by way of illustration only and not limitation. Those skilled in the art will appreciate that many changes may be made to the details of the above-described embodiments without departing from the basic principles of the invention.

Claims (12)

CLAIMS 1. An optical code reader (10, 200, 300) for acquiring an image of an object in a viewing volume, comprising: a housing (20, 310) having an outer opening on its front; a window (64, 364) disposed in said housing (20, 310) adjacent said outer opening; a planar printed circuit board (40, 340) disposed toward the rear of the housing and oriented at a first acute angle relative to the window (64, 364); a primary mirror (62,362) mounted in said housing (20,310) at a second acute angle relative to said window (64,364) for directing in said viewing volume along a first viewing segment path (82,382) a first perspective view of said object; an imager (53, 353) mounted on said printed circuit board (40, 340) adjacent to said primary mirror (62, 362); a secondary mirror (60, 360) disposed in said first viewing segment path (82, 382) to direct said first perspective view of said object towards said imager (53, 353), said imager (53, 353) capable of operating to acquire a two-dimensional image of the object from the first perspective; an illumination system (70, 370) mounted on said printed circuit board (40, 340) for directing illumination light into said observation volume, Wherein said illumination system (70, 370) and said imager (53, 353) are disposed on the same side of said printed circuit board (40, 340). 2. The optical code reader of claim 1, wherein the printed circuit board (40) and the primary mirror (62, 362) are arranged parallel to each other. 3. The optical code reader of claim 1, wherein the printed circuit board (40) is disposed at a first acute angle between 30° and 60° relative to the window (64, 364). 4. The optical code reader of claim 1, wherein the primary mirror (62, 362) is disposed at a second acute angle of between 30° and 60° relative to the window (64, 364). 5. The optical code reader of claim 1, further comprising an optical housing (390), wherein the primary mirror (362) and the secondary mirror (360) are mounted by the optical housing (390) aligned, and mounted on the optical chassis (390), wherein the optical chassis is mounted on the printed circuit board. 6. The optical code reader of claim 5, wherein said optical housing (390) comprises a single piece molded part to which said primary mirror (362) and said secondary mirror (360) are mounted . 7. The optical code reader of claim 1, wherein the illumination system (70, 370) and the imager (53, 353) are disposed on the same side of the printed circuit board (40, 340), but on the Opposite end of primary mirror (62,362). 8. The optical code reader (200) of claim 1, Wherein the imager (228) comprises a 2D imager, which is arranged at the lower part of the housing; a window (220) disposed in the housing adjacent to and parallel to the outer opening; wherein said primary mirror (222) mounted at said first acute angle relative to said window (220) is arranged for converting said first perspective view of said object in said viewing volume along said first viewing segment path (232) leads downward and forward; wherein said secondary mirror (224) disposed in said first viewing segment path (232) is arranged for viewing said first perspective view of said object from said primary mirror (222) along a second segment path (234) guide; The optical code reader also includes a third mirror (226) mounted in the second viewing segment path (234) for converting the first perspective view of the object from the secondary mirror (224) leads to the imager (228). 9. The optical code reader of claim 1, wherein the primary mirror is mounted behind an inner opening in the housing, the primary mirror having a viewable area defined by the inner opening. 10. The optical code reader of claim 9, wherein the primary mirror is mounted via double-sided tape secured to a top reflective surface of the primary mirror. 11. A method for reading an optical code on an object in a viewing volume comprising the steps of: positioning a first imager (53,353), a primary mirror (62,362) and an illumination system (70,370) within a reader housing (20,310) such that the first imager (53,353), the primary mirror (62,362) and The illumination system (70, 370) is supported on a common circuit board (40, 340), wherein the imager is mounted on the common circuit board adjacent to the primary mirror, and the illumination system and the imager are disposed on the on the same side as the common circuit board; positioning a window (64, 364) proximate to and parallel to an opening at one end of said reader housing (20, 310), wherein said primary mirror is mounted in said housing at a second acute angle relative to said window, and the circuit board (40, 340) is oriented at a first acute angle relative to the window (64, 364); directing a first field of view of the first imager (53, 353) from a location of the first imager into the viewing volume from a first perspective via a first mirror set; forming a first image at the first imager (53, 353) of the first field of view from the first perspective into the viewing volume; acquiring said first image using said first imager (53, 353); The optical code is processed based on one or more images acquired by the first imager (53, 353). 12. The method of claim 11, further comprising An optical housing (390) having a one-piece construction is provided, wherein said optical housing (390) has a mounting location for said first mirror group including said primary mirror (362) and secondary mirror (360).