Abstract:
A compact barcode reader is provided in which the imaging lens and a linear sensor are in a straight line path with the barcode (no bend in path). By using a wide angle lens with a short back focus, it is possible to reduce the distance between the barcode and linear sensor to a fraction of what it was in the prior art. In addition, the maximum image height and the downward projection of the sensor are reduced to a fraction of what they were in the prior art. As a result, despite the straight line optical path, compact barcode reader becomes so small that it does not interfere with the operation of the beverage maker.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates generally to beverage makers and, more particularly, concerns a beverage maker including a compact integral optical code reader, such as a barcode reader, to be used with ingredient packages containing optical codes, such as for preparation of a beverage. 
         [0002]      FIG. 1  is a schematic representation of a typical beverage preparation machine of the type which prepares and dispenses coffee and tea. The machine M includes a water supply tank T, which is filled with water, and a water pump P pumps water from the tank T into a heater H. The actual beverage is made by pumping the hot water through a cartridge C which contains a powder, or the like, to form the beverage. An optical code, such as a barcode, B is provided on a lower surface of the cartridge C and is read by a barcode reader R when the cartridge is placed into the machine. The barcode may, for example, provide a description of the beverage to be made and instructions for controlling its preparation. 
         [0003]    As is typical, the barcode reader R includes a linear sensor L and a lens N which focuses the barcode on the sensor L. Typically, the lens N has a focal length greater than 25 mm and the sensor L must be placed at a distance of approximately 100 mm from the barcode. Owing to the significant length of the barcode reader R, it is placed in a crosswise orientation general parallel to the barcode B, and a mirror I is provided to bend the light path so that the barcode may be read at the side of the reader R and reflected lengthwise along the reader. If the barcode reader R did not have the mirror I, it would be positioned vertically and would interfere with the placement of a cup to receive the beverage within the apparatus. Nevertheless, even with its illustrated placement, the barcode reader R is large and cumbersome and, because it projects into the open, can possibly be damaged during use of the machine. 
         [0004]    It would therefore be desirable to have a barcode reader which can be kept within the confines of the vicinity of the cartridge, without projecting substantially beyond that vicinity. 
       SUMMARY OF THE INVENTION 
       [0005]    In accordance with the present invention, a compact barcode reader is provided in which the imaging lens and, preferably, the linear sensor are in a straight line path with the barcode (no bend in path). By using a wide angle lens with a short back focus, it is possible to reduce the distance between the barcode and linear sensor to a fraction of what it was in the prior art. In addition, the maximum image height and the downward projection of the sensor are reduced to a fraction of what they were in the prior art. As a result, despite the straight line optical path, compact barcode reader becomes so small that it does not interfere with the operation of the beverage maker. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    The foregoing brief description and further objects, features and advantages of the present invention will be understood more completely from the following detailed descriptions of presently preferred, but nonetheless illustrative, embodiments of the invention, which reference being had to the accompanying drawings, in which: 
           [0007]      FIG. 1  is a schematic representation of a typical beverage preparation machine of the type which prepares and dispenses coffee and tea, the machine including a bar code reader; 
           [0008]      FIG. 2  is a schematic representation of the beverage machine of  FIG. 1  after a compact barcode reader embodying the present invention has been substituted for the original barcode reader; 
           [0009]      FIG. 3  is an enlarged schematic view of a conventional barcode reader R as seen in  FIG. 1 ; 
           [0010]      FIG. 4  is a schematic representation of the optical system of a compact barcode reader  10  embodying the present invention; 
           [0011]      FIGS. 5A and 5B  (also referred to herein collectively as  FIG. 5 ) are a schematic plan view and side view, respectively, of a first embodiment  10  of a compact barcode scanner embodying the present invention; and 
           [0012]      FIGS. 6A and 6B  are a plan view and side view, respectively, of a second embodiment of a compact barcode scanner in with the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0013]      FIG. 2  is a schematic representation of the beverage machine of  FIG. 1  after a compact barcode reader  10 , embodying the present invention, has been substituted for the barcode reader R. All elements which are identified by the same reference characters as in  FIG. 1  are identical. It should be noted that reader  10  is well out of the user&#39;s way and is in a protected position, confined within the footprint projected by cartridge C. 
         [0014]      FIG. 3  is an enlarged schematic view of a conventional barcode reader R as seen in  FIG. 1 . It will be understood that the barcode is above the mirror I as shown in  FIG. 1 . In addition to the elements already discussed, barcode reader R includes an LED D and a projection lens J, which illuminate the barcode. The physical characteristics of a barcode reader in accordance with the prior art and of compact barcode reader embodying the present invention are summarized in Table 1 below. 
         [0000]    
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Prior 
                 Compact 
                   
                   
               
               
                   
                 Art 
                 Barcode Reader 
                 X 
                 Y 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Focal length (mm) 
                 26.83 
                 6.314 
                 8.34 
                 12.8 
               
               
                 Angle of field 
                 30 
                 66 
                 42 
                 66 
               
               
                 (degree) 
               
               
                 Back focus (mm) 
                 42 
                 7.6 
                 10.8 
                 25.3 
               
               
                 Distance between 
                 102 
                 32 
                 50 
                 50 
               
               
                 object and image 
               
               
                 (mm) 
               
               
                 Maximum image 
                 14.3 
                 4.0 
                 4.0 
                 14.3 
               
               
                 height (mm) 
               
               
                 Width of sensor 
                 28.6 
                 8.0 
                 8 
                 28.6 
               
               
                 (mm) 
               
               
                   
               
             
          
         
       
     
         [0015]    In one conventional barcode reader, the focal length of the imaging lens N is 26.83 mm and it has an angle of field of 30°, which is typical. The back focus b, the distance between the lens N and the linear sensor L, is 42 mm, and the overall distance a between the barcode and the sensor L (represented in the drawing as only the distance to the mirror) must be maintained at 102 mm. For that reason, it is necessary to provide the mirror I so that the barcode reader R could project laterally (in  FIG. 1 ) instead of downward, into the portion of the beverage maker used by the operator. With the optical system of the prior art, the maximum height of the image of the bar code was 14.3 mm and the height dimension c of the sensor L was 28.6 mm. 
         [0016]    Reference is made in Table 1 to the angle of field of a lens. This will be understood to be the angle of view, which is related to a linear dimension of the image on the sensor and the focal length of the lens. In the present context, that would be the angle of view at the image sensor in the direction of image height, which is also referred to herein as the “width” of the sensor. Lenses may be referred to herein as “wide angle” or “normal.” A normal lens will be understood to have an angle of view of approximately 30°. A lens with an angle of view substantially above that will be considered a “wide angle” lens, and a lens with an angle of view substantially below that will be considered a “telephoto.” Referring to Table 1, it will be seen that the prior art barcode readers for beverage makers contained normal lenses. 
         [0017]      FIG. 4  is a schematic representation of the optical system of a compact barcode reader  10  embodying the present invention. Use is made of a wide angle lens  12  which, in the preferred embodiment, has a focal length of 6.31 mm and a field of view of 66°. The back focus b between lens  12  and image sensor  14  is only 7.6 mm, and the wider optical field of the lens  12  permits it to be placed closer to the barcode B, resulting in a total distance a between barcode B and the image sensor  14  of only 32 mm. This permits the maintenance of a straight line path between the barcode B, and the lens  12 , without significant projection of compact barcode reader  10  into the operator&#39;s area of the beverage maker (represented by a phantom image of a cup). In addition, the maximum image height produced by the lens  14  is only 4.0 mm, permitting the use of a sensor  14  with a lateral dimension c of only 8 mm. 
         [0018]    To achieve sufficient compactness of the scanner  10 , it is preferred that the total distance a between barcode B and the image sensor  14  in  FIG. 4  be no greater than approximately 50 mm. The two right hand columns of Table 1 illustrate the dimensions for two alternate embodiments X and Y which achieve a sufficiently compact construction with a total distance a, which is less than approximately 50 mm. Embodiment X utilizes a lens with an 8.34 mm focal length and a 42° angle of field. It can then make use of the same sensor and maximum image size as the first embodiment. The smaller angle of field makes the lens easier to design and manufacture. 
         [0019]    In alternate embodiment Y, the focal length of the lens is increased to 12.8 and an image and sensor size which are the same as the prior art are used. With the wide angle lens, it is still possible to maintain dimension a no greater than approximately 50 mm. 
         [0020]      FIGS. 5A and 5B  (also referred to herein collectively as  FIG. 5 ) are a schematic plan view and side view, respectively, of a first embodiment  10  of a compact barcode scanner embodying the present invention. Scanner  10  includes a circuit board  22  and a case  24  which supports the lens  12  and the image sensor  14 . Also, two LEDs  26 ,  26  are mounted on the circuit board  22  so as to project light to the left (in  FIG. 5 ), to illuminate the barcode. 
         [0021]    Circuit board  22  contains a drive circuit for the sensor  14 , a signal processing circuit, a barcode pattern allows the circuit, an LED drive circuit and a control circuit. For purposes of processing, and it is assumed that the circuit board contains an ASIC with a built-in CPU. The control circuit of the beverage machine may also be built into the ASIC. 
         [0022]    The case  24  is preferably about 13 mm long (left-right dimension in  FIG. 5 ), about 20 mm wide (the height dimension in  FIG. 5A ) and about 8 mm high (the height dimension in  FIG. 5B ). It may be made of any convenient material, such as plastic. It has a provision for retaining the lens  12  and sensor  14  in a required, fixed relationship. Lens  12  is preferably made of plastic, and sensor  14  is preferably a CCD or CMOS image sensor. 
         [0023]      FIGS. 6A and 6B  are a plan view and side view, respectively, of a second embodiment  20 ′ of a compact barcode sensor in accordance with the present invention. In  FIG. 6 , elements identical to those in  FIG. 5  are indicated by the same reference characters. The primary difference is that the sensor  14  is mounted on the circuit board  22 ′, which is otherwise identical to circuit board  22  of  FIG. 5 . An angled mirror  28  is provided to produce a bent optical path to image sensor  14 ′. The dimensions of the barcode reader  20 ′ are essentially identical to those of barcode reader  20 . 
         [0024]    Barcode reader  20  is mounted so that the far (right hand) edge of case  24  is about 34 mm from the barcode, and barcode reader  20 ′ is mounted so that the far edge of case  24  is about 33 mm from the barcode. 
         [0025]    Although preferred embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that many additions, modifications, and substitutions are possible without departing from the scope and spirit of the invention as defined by the accompanying claims.