Patent Publication Number: US-2010127080-A1

Title: Scanning device having adjustable light path

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention generally relates to barcode or similar readers, and more particularly to a scanning device for barcode or similar readers whose light projected path could be adjusted. 
     DESCRIPTION OF THE PRIOR ART 
     Barcode readers using laser light source have the advantage of faster scanning speed but with shorter lifespan and potential hazard to the operator&#39;s eyes. Barcode readers using light emitting diodes (LEDs) as light source, as disclosed by U.S. Pat. Nos. 4,743,773, 5,449,892, 6,119,939, 6,729,546, etc., do not present a threat to the operator but suffers slower scanning speed. Please also refer to Taiwan Patent No. M314,889 and  FIG. 9  for another conventional barcode scanner. As illustrated, the barcode scanner contains a body  80  and a lighting assembly  90 . The body  80  has a front opening  81  for the passage of light. The lighting assembly  90  contains at least a light generation element  91 , at least a light bar  92 , a lens  93 , a light sensor/receiver  94  and a reflective mirror  95 . The light bars  92  are positioned about more than 10 mm in front of the light generation elements  91  and light sensor/receiver  94  is positioned behind the lens  93 . 
     The foregoing prior arts suffer the following shortcomings. First of all, the light generation elements  91  and the light bars  92  cannot be adjusted once installed. However, if there is some misalignment, the projected light is deviated and therefore cannot be appropriately reflected back to the light sensor/receiver  94 . As such, the scanning speed of the barcode reader is significantly impaired. 
     Secondly, the lens  93  of the conventional lighting assembly  90  usually has a built-in stop so that the lens  93  is quite bulky. The body  80  therefore has to be bigger so as to accommodate the lens  93  and the light bars  92  at the lens  93 &#39;s sides. Compared to the light bars  92  and the lens  93 , the much smaller light generation elements  91  are on the other hand positioned separately at a distance. The overall result is significantly inefficient utilization of body  80 &#39;s space. 
     SUMMARY OF THE INVENTION 
     Therefore, s novel scanning device for barcode or similar readers using LEDs as light source is provided herein to obviate the foregoing shortcomings of the prior arts. 
     A scanning device according to an embodiment of the present invention contains a seat, an image sensor at a back side of the seat, and a light generation assembly inside the seat. The light generation assembly contains at least a light generation element, at least a light bar, a lens, and a stop separated from the lens. The lens is positioned in front of the image sensor and the stop is positioned in front of the lens. The light bar at a side of the stop is positioned in front of the light generation element which in turn is at a side of the lens, so as to achieve more efficient space utilization. 
     The light generation element is moveably positioned so that it could be adjusted to overlap its light projected range with the range received by the lens. The image sensor therefore captures the strongest optical signal and allows for a faster scanning speed. 
     The foregoing objectives and summary provide only a brief introduction to the present invention. To fully appreciate these and other objects of the present invention as well as the invention itself, all of which will become apparent to those skilled in the art, the following detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. Throughout the specification and drawings identical reference numerals refer to identical or similar parts. 
     Many other advantages and features of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective diagram showing a scanning device according an embodiment of the present invention. 
         FIG. 2  is a perspective exploded diagram showing the various components of the scanning device of  FIG. 1 . 
         FIG. 3  is a top view diagram showing the scanning device of  FIG. 1 . 
         FIG. 4  is a sectional diagram showing the vicinity of a light generation element inside the scanning device of  FIG. 1 . 
         FIGS. 5A and 5B  are schematic diagrams showing the light projected path from a light generation element of the scanning device of  FIG. 1 . 
         FIG. 6  is a schematic diagram showing the relationship between the range projected by the light generation elements and the range received by the lens of the scanning device of  FIG. 1 . 
         FIG. 7  is a perspective diagram showing the scanning device of  FIG. 1  joined to a circuit board of a barcode reader. 
         FIG. 8  is a sectional diagram showing the adjustment of a light generation element of the scanning device of  FIG. 1 . 
         FIG. 9  is schematic diagram showing the layout of components of a conventional barcode reader. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following descriptions are exemplary embodiments only, and are not intended to limit the scope, applicability or configuration of the invention in any way. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. Various changes to the described embodiments may be made in the function and arrangement of the elements described without departing from the scope of the invention as set forth in the appended claims. 
     As shown in  FIGS. 1 to 4 , a scanning device according to an embodiment of the present invention contains a seat  10 , an image sensor  20 , and a light generation assembly  30 . 
     The seat  10  is walled along its two lateral sides and opened to a front side, a back side, and a top side to form an internal storage space  11 . A transparent plate  12  allowing passage of light is provided to the front side of the seat  10 . The image sensor  20  is provided to the back side of the seat  10  to receive the reflected light when the scanning device is in operation. 
     Two partitions  13  are provided in a middle section of the space  11 , forming two slots  14  in parallel with a gap therebetween and each with gradually enlarged opening towards the front side. At the openings of the two slots  14 , there are vertical grooves  131  and  15 , respectively. Also a cover  16  is provided on top of the partitions  13  and the slots  14 . The cover  16  has a number of through holes  161  and two adjustment holes  162 . The light generation assembly  20  contains two light generation elements (such as light emitting diodes)  31 , two light bars  32 , a lens  33 , and a stop (also called diaphragm)  34 . Please note that the stop  34  is separated from the lens  33 . The two light generation elements  31  are positioned in the slots  14 , respectively. Each light generation element  31  has two flexible terminals  311  and these terminals  311  are extended vertically upward through the through holes  161  of the cover  16 . By pulling or pushing the terminals  311 , the light generation elements  31  could be adjusted inside their respective slots  14 . The lens  33  is held between the partitions  13  in front of the image sensor  20  and the stop  34  is also held between the partitions  13  in front of the lens  33 . The light bars  32  could be cylindrical lenses and they are held in front of the light generation elements  31  by the grooves  15 ,  131  of the slots  14 , respectively. Please note that the above arrangement of the elements of the light generation assembly  30  effectively requires a less amount of space than that required by the prior arts and therefore could help reducing the production cost and the size of the scanning device. 
     Further more, as shown in  FIGS. 3 and 6 , the above arrangement of the elements of the light generation assembly  30  achieves the smallest included angle θ between an axis of the lens  33  and an axis of the light generation element  31 . As such, a projecting range R 1  of the light generation element  31  would nearly overlap a receiving range R 2  of the lens  33 . The image sensor  20  would therefore receive the strongest optical signal, thereby allowing a faster scanning speed. 
     As shown in  FIG. 7 , the scanning device described above is attached to a side of a circuit board  17  containing various electrical elements of, for example, a barcode reader. The circuit board  17  has a number of holes  171  receiving the adjustment holes  162  of the cover  16 . The terminals  311  of the light generation elements  31 , after extending through the through holes  161  of the cover  16 , are soldered to the circuit board  17 . 
     The light generation elements  31  are first aligned with the light bars  32  by manipulating their terminals  311  before being soldered to the circuit board  17 . However, as shown in  FIG. 5A , when the light generation element  31  is a bit below its ideal position relative to the light bar  32 , its projected light path L 1  would be above the ideal path L 3 . In this case, the light generation element  31  should be adjusted upward. Similarly, as shown in  FIG. 5B , when the light generation element  31  is a bit above its ideal position, its projected light path L 2  would be projected too low and it should be adjusted downward to correct the misalignment. 
     As shown in HG  8 , according to the present invention, the slots  14  where the light generation elements  31  are positioned are configured such that some room is reserved for the adjustment of the light generation elements  31 . Together with the flexibility of the terminals  311 , each light generation element  31 &#39;s alignment could be adjusted by using a bar  40  to push against the light generation element through the adjustment hole  162  above the light generation element  31 , or a correspond hole (not numbered) of the seat  10  beneath the light generation element  31 . 
     While certain novel features of this invention have been shown and described and are pointed out in the annexed claim, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention.