Arrangement for, and method of, processing products associated with RFID tags and bar code symbols at the same workstation

A workstation has a metallic housing for supporting an electro-optical reader for reading bar code symbols. A radio frequency (RF) antenna of an RF identification (RFID) reader for reading RFID tags is mounted in a metallic container that is connected to the housing. The RF antenna radiates RF energy at a frequency greater than 900 MHz through RF excitation slots formed between the container and the housing.

BACKGROUND OF THE INVENTION

The present disclosure relates generally to an arrangement for, and a method of, processing products associated with bar code symbols and/or radio frequency (RF) identification (RFID) tags, and, more particularly, to a point-of-transaction, checkout workstation through which the products are passed and processed, while the associated symbols and/or RFID tags are read at the same workstation.

In the retail industry, it is known to read targets, such as one-dimensional bar code symbols, particularly of the Universal Product Code (UPC) type, and two-dimensional bar code symbols, such as Quick Response (QR) codes, associated with, or borne on, retail products or items that are passed through, and processed by, various types of workstations, such as a flat bed scanner having a single horizontal window, or a vertical slot scanner having a single upright window, or a bi-optical scanner having dual horizontal and upright windows. Each such workstation can have either laser-based or imager-based readers for electro-optically reading the symbols passed by, or presented to, either or both windows, and each such workstation is typically fixedly installed and stationarily mounted in a checkout counter.

RFID systems for reading targets are also known and are commonly utilized for product locating, product tracking, product identification, and inventory control in manufacturing, warehouse, retail environments, and like venues. Briefly, an RFID system includes two primary components: an RFID reader (also known as an interrogator), and an RFID tag (also known as a transponder). The tag is a miniature device associated with, or attached to, a product to be monitored and is capable of responding, via a tag antenna, to an electromagnetic RF interrogating wave wirelessly propagated by an RF antenna of the reader. The tag responsively generates and wirelessly propagates an electromagnetic RF return wave back to the reader antenna. The return wave is modulated in a manner that conveys identification data (also known as a payload) from the tag back to the reader. The identification data can then be stored, processed, displayed, or transmitted by the RFID reader as needed.

It has become increasingly common in some venues to provide RFID tags in close proximity to symbols on products, or on shipping cartons containing the products, or on transport pallets that support the products and/or cartons, because the RFID reader can complement the symbol reader in reducing time and labor involved in a number of locating, tracking, identification, and inventory control processes, and can also provide a higher level of accuracy as compared to only relying on the symbol reader when implemented in certain areas of the venue. One such area is checkout, where an electro-optical symbol reader in a stationary workstation is operated to read symbols, and where a separate RFID reader is separately operated to read RFID tags. The RFID reader can advantageously confirm that the products being checked out should be removed from inventory. The RFID reader and the symbol reader are typically contained in separate housings that are remote from each other. For example, the RFID reader can be stationarily mounted overhead on a ceiling of the venue above the workstation, or the RFID reader can be implemented as a portable, mobile device that is movable towards and away from the workstation. The mobile device is typically supported in an operator's hand during use, or is mounted either directly, or in a cradle mounted, on the counter, during non-use.

Although the known symbol and RFID readers are generally satisfactory for their intended reading purposes, the operator needs to operate two different readers at two different times. This not only requires a skilled operator, but also slows down the checkout process, which is undesirable not only from the retailer's, but also from the customer's, point of view. The workstation typically has a housing principally constituted of metal walls that form a metallic chassis. Heretofore, the RFID reader, and particularly its RF antenna, was not integrated with the symbol reader at the same workstation, because the metal housing walls would attenuate, or sometimes even block, the RF interrogating and return waves, thereby degrading the tag reading performance.

Accordingly, it would be desirable to integrate a symbol reader and an RF antenna of an RFID reader at the same workstation, to enable the same workstation to read both symbols and/or RFID tags despite the metal walls of the workstation, and to expedite the overall checkout process.

DETAILED DESCRIPTION OF THE INVENTION

One aspect of the present disclosure generally relates to an arrangement or workstation for processing products associated with targets to be read as they pass through the workstation. The workstation includes a window constituted of a material, such as glass or plastic, that is transmissive to light, and a housing or chassis that supports the window. The housing has housing walls constituted of an electrically conductive material, such as metal. An electro-optical reader is supported by the housing and is operative for reading the targets configured as bar code symbols by detecting return light returning from the symbols and passing through the window. A container is mounted exteriorly of the housing in a mounted position. The container has container walls also constituted of an electrically conductive material, such as metal. The electrically conductive container walls bound at least one radio frequency (RF) excitation slot, and preferably a pair of such RF excitation slots, with the electrically conductive housing walls in the mounted position. An RF identification (RFID) reader includes an RF antenna mounted in the container. The RF antenna is operative for radiating and receiving RF electromagnetic energy at a frequency greater than 900 MHz. The RFID reader is operative for reading the targets configured as RFID tags by transmitting the RF energy radiated by the RF antenna and reflected by the electrically conductive container walls through one or both of the RF excitation slots away from the container to the tags, and by detecting return RF energy returning from the tags through one or more of the RF excitation slots and received by the RF antenna in the container.

Advantageously, the electrically conductive housing walls are spaced apart by a first distance along an advancement direction in which the products are processed and advanced past the window, and the electrically conductive container walls are also spaced apart along the advancement direction by a second distance greater than the first distance to bound the RF excitation slots that are spaced apart along the advancement direction. The window lies in a generally horizontal plane, and the RF excitation slots preferably lie in the same plane as the window. The electrically conductive container walls reflect the RF energy radiated by the RF antenna through the RF excitation slots along a direction that is generally perpendicular to the plane of the window. The RF antenna can be a loop antenna, a dipole, or a like radiator, and is mounted inside the container, and more than one RF antenna can be employed.

In a preferred embodiment, the workstation is a bi-optical workstation whose housing includes a horizontal bed for supporting the window, and an upright raised tower for supporting another window that is also transmissive to the light. An electrically conductive frame surrounds the bed and is spaced therefrom by a gap. The RF excitation slots are situated at opposite sides of the bed and are in open communication with the gap. Thus, the RF energy exits and/or enters the gap outside the workstation. The RFID reader includes an RF control module that is mounted outside or inside the container that is preferably located underneath the workstation. The RF control module controls a transmit power of a transceiver connected to the RF antenna to limit the effective radiated power (ERP) so that the RF antenna radiates the RF energy over a reading zone of limited range relative to the housing. The electro-optical reader is operative for reading the symbols over a reading field, and the RFID reader is operative for reading the RFID tags over a reading zone that preferably at least partly overlaps the reading field.

Still another aspect of the present disclosure relates to a method of processing products associated with targets to be read. The method is performed by supporting a window constituted of a material transmissive to light on a housing having housing walls constituted of an electrically conductive material, and by electro-optically reading the targets configured as bar code symbols by detecting return light returning from the symbols and passing through the window. The method is further performed by mounting a container having container walls constituted of an electrically conductive material exteriorly of the housing in a mounted position, by spacing the electrically conductive container walls away from the electrically conductive housing walls in the mounted position to bound at least one radio frequency (RF) excitation slot, by mounting in the container an RF antenna for radiating and receiving RF electromagnetic energy at a frequency greater than 900 MHz, and by reading the targets configured as RF identification (RFID) tags by transmitting the RF energy radiated by the RF antenna and reflected by the electrically conductive container walls through the at least one RF excitation slot away from the container to the tags, and by detecting return RF energy returning from the tags through the at least one RF excitation slot and received by the RF antenna in the container.

In accordance with this disclosure, a symbol reader and at least an RF antenna of an RFID reader are both integrated at the same workstation, and the same workstation can read both symbols and/or RFID tags despite the metal walls of the workstation. The overall checkout process is expedited, because the symbol and RFID readers are not separately operated at two different times. In fact, both the symbols and the RFID tags can be simultaneously read.

Turning now to the drawings, a retail checkout system100, as depicted inFIG. 1, includes a dual window, multi-plane, bi-optical, point-of-transaction, retail workstation10used by retailers at a retail checkout counter14in an aisle to process transactions involving the purchase of retail products associated with, or bearing, an identifying target, such as the symbols described above. In a typical retail venue, a plurality of such workstations10is arranged in a plurality of checkout aisles. As best seen inFIG. 2, the workstation10has a generally horizontal, planar, generally rectangular, bed window12supported by a horizontal bed26. The bed window12is either elevated, or set flush, with the counter14. A generally rectangular frame50constituted of an electrically conductive material, such as metal, surrounds the bed26and forms a generally rectangular gap52therewith. A vertical or generally vertical, i.e., slightly tilted, (referred to as “upright” hereinafter) planar, generally rectangular, tower window16is set flush with, or, as shown, recessed into, a raised tower18above the counter14. The workstation10either rests directly on the counter14, or preferably, the frame50and workstation10both rest in a cutout or well formed in the counter14.

As best seen inFIG. 5, the bed26has a generally planar, base or horizontal bottom wall36, and the tower18has a generally planar, back or upright rear wall38. As best seen inFIGS. 3-4, the bed26also has a pair of upright side walls42. All the walls of the workstation10are constituted of an electrically conductive material, such as metal. Both the bed and tower windows12,16are typically positioned to face and be accessible to a clerk24(FIG. 1) standing at one side of the counter14for enabling the clerk24to interact with the workstation10. Alternatively, in a self-service checkout, the bed and tower windows12,16are typically positioned to face and be accessible to a customer20.

FIG. 1also schematically depicts that a product staging area102is located on the counter14at one side of the workstation10. The products are typically placed on the product staging area102by the customer20standing at the opposite side of the counter. The customer20typically retrieves the individual products for purchase from a shopping cart22or basket for placement on the product staging area102. A non-illustrated conveyor belt could be employed for conveying the products to the clerk24.

FIGS. 1 and 5schematically depict that the workstation10has a bar code symbol reader40, for example, a plurality of imaging readers, each including a solid-state imager for capturing light passing through either or both windows12,16from a one- or two-dimensional symbol over an imaging field of view (FOV)44. In typical use, the clerk24may process each product bearing a UPC symbol thereon, past the windows12,16by swiping the product across a respective window, or by presenting the product by holding it momentarily steady at the respective window, before passing the product to a bagging area104that is located at the opposite side of the workstation10. The symbol may be located on any of the top, bottom, right, left, front and rear, sides of the product, and at least one, if not more, of the imagers will capture the return light returning from the symbol through one or both windows12,16as an image.

In accordance with this disclosure, a tub or container60, as shown inFIGS. 3-5, is mounted exteriorly of the housing in a mounted position underneath the bottom wall36of the bed26. The container60has a box-like shape with an open top facing the bottom wall36, and has a pair of container side walls62constituted of an electrically conductive material, such as metal. The electrically conductive container walls62bound at least one, and preferably a pair of, radio frequency (RF) excitation slots66with the electrically conductive housing walls42in the mounted position. The RFID reader30includes an RF antenna32mounted in the container60and operative for radiating RF energy at a frequency greater than 900 MHz in a transmit mode, and for receiving return RF energy at a frequency greater than 900 MHz in a receive mode. The container walls62reflect any incident RF energy radiated by the RF antenna32and act as a waveguide to direct the radiated RF energy to and through the slots66and, in turn, to and through the aforementioned gap52. As described below, the RFID reader30is operative for reading the targets configured as RFID tags by transmitting the RF energy radiated by the RF antenna32and reflected by the electrically conductive container walls62through each RF excitation slot66and the gap52away from the container60to the tags in the transmit mode, and by detecting return RF energy returning from the tags through the gap52and each RF excitation slot66and received by the RF antenna32in the container60in the receive mode.

As previously mentioned, either or both windows12,16is transmissive to light, for example, is constituted of glass or plastic. In the case of imaging readers, an illumination source emits illumination light in one direction through the windows12,16, and the return illumination light that is reflected and/or scattered from the symbol passes in the opposite direction to the imagers. In the case of moving laser beam readers, a laser emits laser light in one direction through the windows12,16, and the return laser light that is reflected and/or scattered from the symbol passes in the opposite direction to a photodetector.

The bed26and the tower18of the workstation10together comprise a housing or chassis for supporting the windows12,16. The housing has housing walls constituted of an electrically conductive material, such as metal. The housing may be formed in sheet or cast metal, such as aluminum, steel, zinc, magnesium, or a metal-coated structural member. As previously mentioned, such metal housing walls could attenuate, or sometimes even block, the RF interrogating and return waves, and degrade the RFID reader performance. However, in accordance with this disclosure, the metal housing walls are used to advantage, and the RF antenna32is positioned such that there is little, or no, degradation in the performance of the RFID reader.

As shown inFIGS. 3-5, the RF antenna32is mounted underneath the housing in the container60. The RF antenna32is shown inFIG. 3as a generally rectangular loop that is constituted of a flexible conductor, e.g., a metal wire of approximately 20 AWG (American Wire Gauge). Although the loop is illustrated as having a generally rectangular contour, it will be understood that the loop may have other contours, such as generally circular, oval, or other polygonal shapes. The RF antenna32need not be a loop, but can be a dipole, or any other RF radiator. The RF antenna32could also be a conductive strip applied on a printed circuit board. More than one RF antenna could be positioned in the container60. Each antenna can be oriented in either a horizontal or an upright plane. An antenna can be positioned directly underneath each slot66.

The container60bounds an interior cavity or metallic enclosure in which the RF antenna32is mounted. When the RF antenna32radiates RF energy, the RF energy initially fills the cavity, and then passes and spills out of the cavity through the excitation slots66. The metal walls62of the container60assist in reflecting the radiated RF energy through the slots66and the gap52along a direction that is generally perpendicular to the plane of the window12. As an alternative, or in addition, to positioning the RF antenna32in a horizontal plane underneath the bottom wall36, the container60and the RF antenna32can be positioned in a vertical plane in the tower18, in which case, the metal walls62of the container60would reflect the radiated RF energy along a direction that is generally perpendicular to the plane of the window16.

The metal housing walls42are spaced apart by a first distance along an advancement direction in which the products are processed and advanced past the windows12,16. The metal container walls62are spaced apart along the advancement direction by a second distance greater than the first distance to bound the RF excitation slots66that are also spaced apart along the advancement direction. The RF excitation slots66lie in the same plane as the window12, and the metal container walls62reflect the RF energy radiated by the RF antenna32through the RF excitation slots66and the gap52along a direction that is generally perpendicular to the plane of the window12. An RFID tag can be read when entering either side of the workstation10.

The RF energy preferably lies in the industrial, scientific, and medical (ISM) frequency band of about 902 MHz to about 928 MHz. The wavelength at such frequencies is about thirteen inches. Each slot66is preferably dimensioned to be greater than a half-wavelength, i.e., greater than about 6.5 inches. The size of the container60can be adjusted by providing a movable container wall.

As shown inFIGS. 3 and 5, the RFID reader30includes an RF control module34for controlling, among other things, a transmit power of a transceiver connected to the RF antenna32to limit the effective radiated power (ERP) so that the RF antenna32radiates the RF energy over a reading zone of limited range, for example, less than ten inches, above the plane of the window12. Unless so controlled, the RF reader might read RFID tags that are not of interest, for example, tags located on products on shelves in the venue. The RFID reader is thus controlled to read only tags of interest, i.e., tags at the workstation10. The RF control module34may be mounted inside or outside the container60.

As also shown inFIG. 5, the symbol reader40is operative for reading the symbols over a reading field, such as the imaging field of view44, and the RFID reader is operative for reading the RFID tags over a reading zone46that at least partly overlaps the imaging field of view44. The workstation10is operatively connected, either by a wired or a wireless connection, to a remote host server (not illustrated), and the data read by the symbol reader and/or by the RFID reader is advantageously sent to the host server over a shared, common connection to avoid having to install additional connectors on the workstation.

In the foregoing specification, specific embodiments have been described. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the invention as set forth in the claims below. Although the workstation10has been illustrated as a dual-window workstation, it will be understood that the readers30,40could be installed at other types of workstations, for example, a flat bed scanner having a single horizontal window, or a vertical slot scanner having a single upright window. Any metal materials used in the workstation10, or the container60, or the frame50may be formed in sheet or cast metal, such as aluminum, steel, zinc, magnesium, or a metal-coated structural member. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of present teachings.