Abstract:
A bar code reader indicator feature gives visible indication that a bar code function has been performed. The feature is integrally molded with the exit window to simplify the design and reduce cost. The feature can diffuse light from an existing indicator light within the reader or the scanning light beam can be directed to impinge upon an area of the exit window not normally in the beam path when the function has been performed to illuminate the feature.

Description:
TECHNICAL FIELD 
   The invention relates generally to the filed of optical scanners for bar code reading and more particularly to the feedback mechanisms that inform a scanner use the scanner&#39;s beam has been activated. 
   BACKGROUND 
   Various optical scanning systems and readers have been developed heretofore for reading indicia, such as bar code symbols appearing on a label or on the surface of an article. The bar code symbol itself is a coded pattern of graphic indicia comprised of a series of bars of various widths spaced apart from one another to bound spaces of various widths, the bars and spaces having different light reflecting characteristics. The readers function by electro-optically transforming the spatial pattern represented by the graphic indicia into a time-varying signal, which is in turn decoded into data which represent the information or characters encoded in the indicia that are intended to be descriptive of the article or some characteristic thereof. Such data is typically represented in digital form and utilized as an input to a data processing system for applications in point-of-sale processing, inventory control, distribution, transportation and logistics, and the like. Scanning systems and readers of this general type have been disclosed for example, in U.S. Pat. Nos. 4,251,798; 4,369,361; 4,387,297; 4,409,470; 4,760,248; 4,896,026; 5,015,833; 5,262,627; 5,504,316; 5,625,483; and 6,123,265, all of which have been assigned to the same assignee as the instant application each of which is hereby incorporated by reference herein in its entirety. As disclosed in some of the above patents, in one embodiment such a scanning system resides, inter alia, in a hand-held portable laser scanning device supported by a user, which is configured to allow the user to aim a scanning head of the device, and more particularly, a light beam, at a targeted symbol to be read. 
   The light source in a laser scanner bar code reader is typically a semiconductor laser. The use of semiconductor devices as the light source is advantageous because of their small size, low cost and low voltage requirements. The laser beam is optically modified, typically by an optical assembly, to form a beam spot of a certain size at the target distance. The laser light beam is directed by a lens or other optical components along a light path toward a target that includes a bar code symbol on the target surface. 
   Many types of bar code readers, including hand-held readers, have a user feedback feature that gives a visual or audio indication that the scanner has been activated and/or that the decode is successful. This user feedback feature is often an LED that is illuminated to indicate that the beam is activated or that a decode is successful. The LED may be visible to the user through a window in the reader housing or coupled to a light pipe that directs the light to a location outside of the scanner housing. While providing valuable feedback to a reader user, the LED and light pipe add cost and complexity to the reader. 
   SUMMARY 
   By providing an indicator feature that is molded integrally with the exit window, the cost and complexity of a bar code reader can be reduced. A bar code reader that acts upon a bar code on a target surface includes a light source that produces a light beam, a scan engine that directs the light beam through a scanning excursion, an exit window through which the light beam exits the bar code reader, and an indicator feature that is integral to the exit window. The indicator feature provides visible feedback to a user regarding the functioning of the bar code reader, such as when the bar code reader has successfully decoded a bar code or when an error in decoding has occurred. 
   In most cases, the exit window includes a normal operating portion through which the light beam passes when the bar code reader is acting upon a bar code. The indicator feature may be molded into one or more portions of the exit window outside the normal operating portion such that when the light beam passes through the indicator feature, an image of the indicator feature is projected onto the target surface. In this case a scan engine controller may direct the light beam to pass through the indicator feature when a specified function of the bar code reader has occurred. Alternatively, the indicator feature may be molded at a distal end of a light pipe integrally molded with and projecting from a portion of the exit window outside the normal operating portion. In this case as well, the scan engine controller may direct the light beam to pass through the indicator feature when a specified function of the bar code reader has occurred. 
   An existing decoder light source that is present, for example, on a circuit board that houses the decoder can be made visible outside the bar code reader through the indicator feature, which is integral with the exit window. For example, the indicator feature can be a diffuser that diffuses light from the decoder light source. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is cut away of a typical hand-held bar code scanner; 
       FIG. 2   a  is a front view of a bar code reader exit window constructed in accordance with one embodiment of the present invention; 
       FIG. 2   b  is a cross section view of the exit window of  FIG. 2   a;    
       FIG. 3  is a cross section view of a bar code reader exit window constructed in accordance with one embodiment of the present invention; 
       FIGS. 4   a  and  4   b  are cross section views of a bar code reader exit window constructed in accordance with one embodiment of the present invention; and 
       FIG. 5  is a flowchart outlining a method of providing user feedback in accordance with one embodiment of the present invention. 
   

   DESCRIPTION 
     FIG. 1  illustrates a typical hand-held bar code reader  100 . The reader includes a printed circuit board  101  that slides into a housing handle  102  in a generally vertical or upright fashion. A housing, shown as a cutaway outline, envelops the circuit board, light source, and other reader components. The housing consists of the handle  102  and a barrel or canopy  104  molded in a fashion similar to that known in the art. The circuit board  101  supports a scan engine  105 , a trigger switch  106 , and related electronics  122  connected to a controller  124 . The scan engine  105  controls components that cause the beam to oscillate back and forth with a controlled amplitude in substantially linear excursion across the exit window. The outgoing laser beam passes through a slot  114  in the circuit board and is clipped by the exit window edges  115  of the housing so it is usable almost to the end of the scan line. 
   As discussed in the Background, it is common for a reader to provide an audible or visible indication to a user that the reader has been activated. Usually, a separate LED is used to signal activation and light from the LED can be visible through a window or opening in the reader housing or transported via a light pipe to an indicator in the housing. In some cases, the light pipe is overmolded with the housing, which adds cost to the reader.  FIGS. 2-4  illustrate visible activation indication features that are incorporated into the exit window, which simplifies the reader design and construction. The exit window is molded from plastic, typically a polycarbonate or acrylic, so that an elongated projection of the exit window material can serve as an optical fiber and transmit light from the exit window to an area visible to the user. 
     FIGS. 2   a  and  2   b  show an exit window  116 ′ that has been modified from the exit window  116  shown in  FIG. 1  to include two pairs of scanner function indicator patterns  150 ,  151  around a periphery  116 ′ b  of the exit window. Referring to  FIG. 2   b , in normal operation the outgoing laser beam from the scanner passes through the central portion of the exit window “A”. The peripheral area “B” at the edges of the exit window is not encountered by the beam during reading of a bar code. In the scanner function indicator pattern area  150  special structure is incorporated into the exit window periphery  116 ′ a  so that when the beam passes through the periphery, the beam is modified in a certain way to create an identifiable pattern on the target area. More than one type of identifiable pattern may be used to indicate more than one type of scanner function. For example, the pattern area  150  may be used to indicate a successful decode, while the pattern area  151  may be used to indicate a decode error. To utilize this successful decode indication feature, when a successful decode is achieved, the scan engine  105  is actuated to direct the outgoing beam through the appropriate scanner function indicator pattern area  150  to illuminate the special structure. The beam may be held in this position so that the feature is continuously illuminated or the amplitude of oscillation may be increased so that on each pass of the beam after a successful decode the feature is illuminated. Alternatively, the scan engine can direct the beam through several scanner function indicator patterns can in series to create a series of images on the target surface. 
   The scanner function indicator pattern on the exit window can be created in many ways. By nature it can be a diffractive or refractive type of structure. The pattern can be advantageously molded such that the structure is incorporated directly on the surface of the window at little or no additional cost. A diffractive structure may generate a pattern including letters, words, logos, and pictures, such as a company logo or a check mark. While easier to manufacture, a refractive structure may be limited to simpler patterns such as lines, crosses, and dots. 
     FIG. 3  shows a modified exit window  116 ″ that incorporates an integral decode indicating light diffuser  121  that projects to the housing from the top edge of the exit window. The diffuser  121  is positioned such that light from the successful decode indicator LED  130  on the top of the circuit board  112  passes through the diffuser and is made visible to the user. The LED is illuminated to indicate a successful decode and/or activation of the beam. The diffuser directs the LED&#39;s light to the user. The bottom surface of the diffuser may include surface features that better distribute light toward the user. 
     FIG. 4   a  shows an exit window  116 ′″ that has an integral light pipe  117  molded at one of its edges outside the scanning area. As with the modified exit window  116 ′, this decode indicator utilizes light from the beam itself as it passes through the periphery of the exit window to provide visible feedback to the user when a successful decode is achieved. When a decode is complete, the scan engine causes the laser beam to pass through the peripheral area. When the laser beam enters the light pipe it is guided outside the reader housing as shown in  FIG. 4   b . The laser beam can be held stationary at the periphery to maintain constant illumination via the light pipe or the laser beam&#39;s oscillation may be increased in amplitude so that on each pass the beam is routed through the light pipe. 
     FIG. 5  is a flowchart outlining a method  200  for providing feedback regarding scanner function, in this case a successful decode or a decode error. At  210  the scan engine directs the beam through the normal scanning area of the exit window. At  220  the scan engine receives a signal indicative of whether the decode was successful or not. If the decode was successful, the scan engine directs the beam to a success indicator area on the exit window ( 230 ). If a decode error has occurred, the scan engine directs the beam to an error indicator area on the exit window ( 240 ). 
   As can be seen from the foregoing description, incorporating scanner function indication features into the exit window of a bar code reader can simplify the design and construction of the reader. While multiple embodiments of the invention have been illustrated and described in detail, the present invention is not to be considered limited to the precise constructions disclosed. Various modifications, adaptations and uses of the invention may occur to those skilled in the art to which the invention relates. The intention is to cover all such modifications, adaptations and uses falling within the spirit or scope of the claims.