Abstract:
An item checkout device with antenna which provides better overlap between barcode label and radio frequency identification (RFID) label reader reading zones. The antenna may be flush mounted within an aperture of a weigh plate and be electrically isolated from a remainder of weigh plate by an insulator. The antenna may include a section of the weigh plate that has been removed, reduced in size to accommodate the insulator, and inserted into the weigh plate. The antenna may be wirelessly coupled to the RFID label reader to avoid placing any mechanical load on the weigh plate.

Description:
BACKGROUND 
       [0001]    Barcode scanners are well known for their usefulness in identifying products. Barcode scanners may be equipped with add-on radio frequency identification (RFID) label readers, but barcode label and RFID label reading zones do not coincide, resulting in operator confusion as to item placement. Further, finding space for a RFID label reader antenna is a challenge. 
         [0002]    It would be desirable to better integrate RFID label readers with barcode scanners and provide better overlap between barcode label and RFID label reading zones. 
       SUMMARY 
       [0003]    An item checkout device with antenna is provided. 
         [0004]    The antenna may be flush mounted within an aperture of the weigh plate and electrically isolated from a remainder of the weigh plate by an insulator. The antenna may include a section of the weigh plate that has been removed, reduced in size to accommodate the insulator, and inserted into the weigh plate. 
         [0005]    In a preferred example, the antenna is wirelessly coupled to a radio frequency identification (RFID) label reader to avoid placing any mechanical load on the weigh plate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a block diagram of an example item checkout device. 
           [0007]      FIG. 2  is a view illustrating an example antenna configuration. 
           [0008]      FIG. 3  is a view illustrating another example antenna configuration. 
           [0009]      FIG. 4  is a view illustrating another example antenna configuration. 
           [0010]      FIG. 5  is a view illustrating another example antenna configuration. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    Referring now to  FIG. 1 , example item checkout device includes laser  12 , mirrored spinner  14 , pattern mirrors  16 , collector  18 , detector  20 , scale assembly  22 , weigh plate  24 , radio frequency identification (RFID) label reader  26 , and control circuitry  26 . 
         [0012]    Laser  12  generates a laser beam. 
         [0013]    Mirrored spinner  14  directs the laser beam towards pattern mirrors  16  and directs light reflected from item  50  towards collector  18 . Motor  34  rotates mirrored spinner  28 . Pattern mirrors  16  produce a pattern of scanning light beams for scanning barcode label  52  on item  50 . Pattern mirrors  16  direct the laser beam through window  30  in weigh plate  24  towards item  50  and direct the light reflected from item  50  towards mirrored spinner  16 . 
         [0014]    Collector  18  directs the light reflected from item  50  towards detector  20 . 
         [0015]    Detector  20  converts the light reflected from item  50  into electrical signals. 
         [0016]    Scale assembly  22  produces electrical signals based upon the weight of produce items placed on weigh plate  24 . Scale assembly  22  may include a load cell or other weight measuring device. 
         [0017]    Item  50  may be labeled only with barcode label  52 , only with RFID label  54 , or both. 
         [0018]    RFID label reader  26  wirelessly interrogates RFID label  54  on item  50 . RFID label reader  26  couples to RFID label reader antenna  32 . 
         [0019]    Control circuitry  28  controls operation of item checkout device  10 . Control circuitry  28  receives electrical signals from detector  20  and determines item identification information stored within barcode label  52 . Control circuitry  28  receives weight signals from scale assembly  22 . Control circuitry  28  receives item identification information stored within RFID label  54  from RFID label reader  26 . Control circuitry  28  sends weight information and item identification information to point-of-sale (POS) terminal  60 . 
         [0020]    POS terminal  60  determines a price of item  50  based upon the item identification information. POS terminal  60  also determines prices of produce items based upon the weight information and produce identification information entered into POS terminal  60  by an operator. 
         [0021]    With reference to  FIG. 2 , a first example RFID label reader antenna  32  is illustrated. 
         [0022]    RFID label antenna  32  includes two portions  32 A and  32 B. Antenna portion  32 A is connected to RFID label reader and is located underneath weigh plate  24 . Antenna portion  32 B is part of weigh plate weigh plate  24 , in a position directly above antenna portion  32 A. 
         [0023]    Antenna portions  32 A and  32 B form a circularly polarized antenna. The operating frequency is in the Industrial, Scientific, and Medical (ISM) band from 902-928 MHz (center frequency 915 MHz). The sizes of antenna portions  32 A and  32 B are about a half a wavelength square, in this case, about 6.5 inches by 6.5 inches. 
         [0024]    Antenna portions  32 A and  32 B couple wirelessly. Antenna portion  32 B acts as a resonator for the RF signal from antenna portion  32 A. 
         [0025]    Wireless coupling, as opposed to connecting RFID label reader  26  to weigh plate  24  with a wire, avoids placing any mechanical load on weigh plate  24 . The weight information reported by scale assembly  22  is not affected by antenna portions  32 A and  32 B. 
         [0026]    The orientation of antenna portions  32 A and  32 B results in an antenna pattern that points upward with minimum radiation to the sides. This limits the RFID reading zone to approximately the barcode scanning zone, such that RFID labels on items in shopping carts or over scanners in adjacent lanes are not read by RFID label reader  28 . 
         [0027]    In more detail, antenna portion  32 A as illustrated is mounted to a top layer  42  of printed circuit board  38 . Antenna portion  32 A is fed with a microstrip transmission line  40  on the layer  44  below. Microstrip transmission line  40  wirelessly couples to antenna portion  32 A. 
         [0028]    Antenna portion  32 A may be of any arbitrary design and may be fed with a wired or wireless connection to microstrip transmission line  40 , a coax cable, or any other conductor suitable for RFID label reader  26 . 
         [0029]    Antenna portion  32 B may be cut out from a cutout from weigh plate  24 . The cutout is slightly reduced in size and reinserted within aperture  38  with a ring  36  of insulating or non-conductive glue around the perimeter in order to achieve electrical isolation from the rest of weigh plate  24 . Antenna portion  32 B remains flush with the top surface of weigh plate  24 . 
         [0030]    Antenna portion  32 B is illustrated as having a generally octagonal shape. Other shapes are also envisioned. 
         [0031]    Antenna portions  32 A and  32 B would normally be placed close to the resonating patch to maximize coupling and efficiency, but placement at a larger distance is also possible. The size of the RFID read zone may be controlled by adjusting the output power from RFID label reader  26 . 
         [0032]    Antenna portion  32 B may be located anywhere around window  30  without obscuring the laser beam or returning light from entering or leaving optics cavity  48 . The illustrated location is between window  30  and an operator end of device  10 . Housing  62  of item checkout device  10  may be manufactured to provide shelf area  46  underlying weigh plate  24  for mounting printed circuit board  38 . 
         [0033]    With reference to  FIG. 3 , a second embodiment is illustrated in which the antenna  32  in weigh plate  24  is driven by coupling circuit  70 . Coupling circuit  70  may be capacitive or inductive. 
         [0034]    With reference to  FIG. 4 , a third embodiment is illustrated in which the antenna  32  is an aperture antenna. The radiating element is not an area of weigh plate  24 , but is aperture  38  in weigh plate  24 . Radiation is caused by currents around aperture  38 . Aperture  38  is filled with a blank  80  made of a non-conductive material, such as plastic. 
         [0035]    Other shapes are also envisioned, such as a simple slot, a square, a circle, or a ring shape. 
         [0036]    Antenna  32  may be excited by either of the methods in  FIGS. 2 and 3 . 
         [0037]      FIG. 5  illustrates an alternate location and an alternate shape for antenna  32 . The shape is generally in the form of a letter “C”, and the location is around window  30 . 
         [0038]    Antenna  32  may be any of the types in  FIGS. 2 and 4 , and may be excited by either of the methods in  FIGS. 2 and 3 . 
         [0039]    Although particular reference has been made to certain embodiments, variations and modifications are also envisioned within the spirit and scope of the following claims.