Abstract:
An optical scanner comprising a weigh scale is presented with a self-centering top plate. The design of the top plate creates a horizontal gravitation vector on objects placed on and away from the center of the top plate. The force vector is directed toward the center of the top plate and diminishes to zero as the object approaches the center of the top plate.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to optical code scanners. More particularly, but not exclusively, the invention relates to optical code scanners with an integrated weigh scale. 
       BACKGROUND 
       [0002]    In a general retail environment where groceries are sold, it is common for a point-of-sale (POS) terminal to include an item scanning device and for the item scanning device to have an integrated item weigh scale. The item scanning device scans an item presented to the POS terminal and if an optical code is found, reads the optical code and communicates the information to the POS terminal. The weigh scale determines the weight of one or more items placed on the weigh scale&#39;s “top plate” or “weigh plate” as it is sometimes referred to. 
         [0003]    The top plate (horizontal surface) of a bi-optic item scanning device has a centered area composed of an optically transparent material to allow light, including laser light, to pass through. Whether the item scanning device is based on imaging or laser technology (or both), at least a portion of the top plate must allow light to pass through with a minimum of optical distortion and attenuation. This dictates the use of an optically clear material formed into a flat sheet with uniform thickness. The optically clear material is typically enclosed with a strong material for support. This material is can be a metal such as stainless steel. A top plate that meets these requirements is a major cost component of the item scanning device. In additional, items placed on the top plate will sometimes roll off or move around causing weighing errors or delays in reading the weigh of the item. 
         [0004]    Thus, a need exists for a weigh scale device that has a lower cost top plate designed to center items placed on the top plate. 
       SUMMARY OF THE INVENTION 
       [0005]    Among its several aspects, the present invention recognizes a condition wherein the top plate of weigh scale represents a major cost component of the weigh scale and that items placed on the top plate are prone to roll off or remain in motion. These conditions prevent the development of lower cost scale and slow down the process of weighing items. 
         [0006]    The invention addresses these problems, as well as others, by recognizing that scanning technology has improved to point where horizontal item scanning is not always required to maintain a high first pass success rate for scanning an item. This allows the portion of the top plate comprising the optically clear material to be removed. The top plate is now composed of a low cost durable material. In addition, the top plate is formed into a concave shape that self-centers items placed on the top plate. This prevents them from rolling off and dampens their movement. 
         [0007]    The upper surface of the top plate has a neutral color and finish to reduce specular reflections and improve the ability to identify an item placed on the top plate. In addition, the low cost durable material of the top plate is translucent to light projected onto the under side of the top plate. The translucent light that passes through the top plate is used to better define or silhouette the outline of items placed on the top plate for identification. 
         [0008]    A more complete understanding of the present invention, as well as further features and advantages of the invention, will be apparent from the following Detailed Description and the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a high-level block diagram illustrating an exemplar embodiment of an item scanner in a retail environment. 
           [0010]      FIG. 2  is a drawing of an item scanner used in an exemplar embodiment of the present invention. 
           [0011]      FIG. 3A  is a first cross section drawing of a top plate of an item scanner used in an exemplar embodiment of the present invention. 
           [0012]      FIG. 3B  is a second cross section drawing of the top plate of the item scanner used in an exemplar embodiment of the present invention. 
           [0013]      FIG. 4  is a partial cross section drawing of an item scanner. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    In the following description, numerous details and embodiments are set forth to provide an understanding of the claimed invention. However, it will be appreciated by those skilled in the art that various modifications to the described embodiments may be made without departing from the spirit and scope of the invention and that numerous variations or modifications from the described embodiments are possible. Throughout this specification, like numbered elements are used to describe the same parts throughout the various drawing figures referred to and described. 
         [0015]    Referring to  FIG. 1 , there is provided a high-level block diagram illustrating an exemplar embodiment of an item scanner  110  in a retail environment  100 . The retail environment  100  includes a store server  145  in communication with a point-of-sale (POS) terminal  140  over a network  150 . A typical retail environment  100  has multiple POS terminals  140 . The POS terminal  140  includes a number of devices and peripherals and can be configured to be either an assisted or self-service checkout terminal. An item scanner  110  is attached to the POS terminal  140 . The item scanner  110  includes a processing module  130  that controls the functions of the item scanner  110 . The item scanner  110  further includes the following hardware components: laser scanning hardware  115 , image scanning hardware  125 , weigh scale hardware  120  and communication hardware  135 . 
         [0016]    The communication hardware  135  provides the hardware to communicate with the POS terminal  140 . The processing module  130  includes a processor, memory and hardware that allows the processor to communicate with and control the hardware components of the item scanner  110 . The memory includes software instructions that when executed by the processor cause the processor to control the hardware components and implement the features and functions of the item scanner  110 . 
         [0017]    The memory provides both persistent and short term memory. Updates to the software instructions can be sent to the item scanner  110  by the POS terminal  140 . These instructions can be provided directly to the POS terminal  140  or by the store server  145 . The updates to the software instructions can be stored on a portable memory device that is attached to the POS terminal  140  or the store server  145 . Once attached, the updates to the software instructions are read from the portable memory device and sent to the item scanner  110  for storage and execution by the item scanner  110 . In some embodiments, the updates to the software instructions are retrieved from, or automatically sent from a central server over the Internet or some other wide area network to the store server  145  and then sent to the item scanner  110 . There maybe one or more intermediate servers between the store server  145  and the central server. 
         [0018]    In some embodiments, the item scanner  110  includes either the laser scanning hardware  115  or the image scanning hardware  125  but not both. In still other embodiments, an external camera (not shown) is attached to either the item scanner  110  or the POS terminal  140 . The external camera is adapted to recognize produce and to captures photos of documents presented to the POS terminal  140 . The external camera is often located above the item scanner  110  and directed down towards the item scanner  110 . In embodiments without an external camera, an image capture device in the image scanning hardware  125  can be used to recognize produce and capture photos of documents. 
         [0019]    Turning to  FIG. 2 , there is provided a drawing of an item scanner  110  used in an exemplar embodiment of the present invention. The item scanner  110  uses a vertical window  215  to scan for optical codes. The plane of the vertical window  215  is typically angled off the vertical or z-axis  240 . In this embodiment, the optical codes are bar codes which include both one-dimensional and two-dimensional bar codes. The bar codes are typically attached to items presented to the POS terminal  140  for purchase. In some cases, one or more bar codes maybe attached to or printed on a sheet of paper. These bar codes are for products or services that because of the nature of the products or services are not easily presented to the POS terminal  140  for purchase. Examples of these products or services are: a 50 pound bag of dog food or ice stored in an outside ice machine or an oil change for a vehicle. In these cases, a bar code for the related product or service that is printed on a sheet is scanned. Both the laser scanning hardware  115  and image scanning hardware  125  use the vertical window  215  to read bar codes. 
         [0020]    The item scanner  110  includes weigh scale hardware  120  that determines the weight of an item or items placed on a top plate  220  and then communicates the weight to the POS terminal  140 . The top plate  220  forms the lower or horizontal surface of the item scanner  110  and has a geometric center  225 . For reference, an x-axis  230  is provided that is parallel to the front edge of the item scanner  110  and an y-axis  235  that is parallel to the side edge of the item scanner  110 . 
         [0021]    Turning to  FIG. 3A , there is provided a first cross section drawing of a top plate  220  of the item scanner  110  used in an exemplar embodiment of the present invention. The top plate  220  is designed to have a concave shape as illustrated in  FIGS. 3A and 3B . The center of curvature  315  for the top plate  220  is located above the item scanner  110  on the principal axis  310  of the top plate  220  which intersects the top plate  220  at the geometric center  225 . This point is also referred to as the vertex  320  of the principal axis.  FIG. 3A  depicts a cross section of the top plate  220  where the section is parallel to x-axis  230  and cuts through the center  225  of the top plate  220 . The depth  305  of the top plate curvature is measured at the center  225  of the top plate  220  and is the distance from the upper surface of the top plate  220  to a straight line parallel to the x-axis  230  and passing through the two upper side edges of the top plate  220   
         [0022]    Turning to  FIG. 3B , there is provided a second cross section drawing of a top plate  220  of the item scanner  110  used in an exemplar embodiment of the present invention.  FIG. 3B  depicts a cross section of the top plate  220  where the section is parallel to y-axis  235  and cuts through the center  225  of the top plate  220 . The depth  305  of the top plate curvature is the same as in  FIG. 3A  however, the straight line in this figure is parallel to the y-axis  235  not the x-axis  230 . 
         [0023]    The depth  305  for a top plate  220  can vary between different embodiments depending on the overall dimensions of the top plate  220  while still keeping the center of curvature  315  at the same location above the top plate  220  for the same dimension (x or y). If the top plate  220  is a rectangular shaped plate, the location of center of curvature will be different for the x-axis and y-axis. If the top plate  220  is a square plate, the location of the center of curvature is at the same location for both axes. Typical values for the depth  305  range from 0.1″ to 0.5″ (inches). In addition, scanners  110  with a larger top plate  220  could have a larger depth  305  and center of curvature  315  that is further away from the top plate  220 . 
         [0024]    Turning to  FIG. 4 , there is provided a partial cross section drawing of an item scanner  110 . The top plate  220  is depicted with a driver&#39;s license  410  laying face up centered on the upper surface of the top plate  220 . A light source  405  is located under the top plate  220  and inside the item scanner  110 . The light source  405  directs light  415  to and illuminates the underside of the top plate  220  (area  425 ). The top plate  220  is constructed of a translucent material that transmits a portion of the light from the light source  405  through to the upper side of the top plate  220  creating a diffuse light source on the upper side of the top plate  220  (area  430 ). The diffuse light from the top plate  220  provides an outline of objects placed on the top plate  220 . Here, the edges of the driver&#39;s license are clearly outlined  420  by the diffuse light. This improves the ability of software to process a photo of the driver&#39;s license  410 . A photo of the driver&#39;s license can be captured by a camera not located in the item scanner  110  or an image capture device that is part of the item scanner  110  can be used. The diffuse light also aids in recognizing products or other objects placed on the top plate  220  by clearly defining the edges of the object. 
         [0025]    The upper surface of the top plate has a neutral color and finish. This can be a painted on color and finish or it can be inherent to the material that composes the top plate. In this embodiment, a charcoal color is used but other embodiment can use different neutral colors. To reduce specular reflections, a matte finish is used. 
         [0026]    Although particular reference has been made to an item scanner  110  used a retail environment and examples have been provided illustrating the invention, certain other embodiments, variations and modifications are also envisioned within the spirit and scope of the following claims.