Registers – Coded record sensors – Particular sensor structure
Reexamination Certificate
2001-02-20
2003-10-14
Lee, Michael G. (Department: 2876)
Registers
Coded record sensors
Particular sensor structure
C235S494000, C235S462010, C235S462070, C235S456000, C235S436000
Reexamination Certificate
active
06631843
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a composite code having two parts encoded using different coding schemes and located adjacent to each other. The two parts are associated by a link-flag adjacent at least one of the two parts.
BACKGROUND OF THE INVENTION
Bar Code Symbology
Optically encoded indicia, such as bar codes are well known in the art. Today, bar codes are used in just about every type of business application: point-of-sale, retail, warehousing, etc. Bar codes are printed on substrates, individual items and on containers enclosing a number of items. Bar codes carry information encoded into bars and spaces of various width, arranged in a predetermined patterns. The bars and spaces are made up of unit elements called modules. A module has a specified height and width. Width is usually called the horizontal dimension of the module. When a bar code is scanned by a laser scanner, bar code modules are usually crossed by the scanning beam along its horizontal dimension. The relative size of a bar coded label is determined by the type of coding used, as are the actual sizes of the label's individual bars and spaces. The size of the bar code is also directly proportional to the amount of information that is stored in that bar code. Conversely, the amount of information is constrained by the size limitations on the bar code. Bar codes usually get scanned via a bar code scanning system, and the encoded information gets extracted and decoded by the system's processing means. Bar code reading can be accomplished by scanning across the bar code with a laser scanner, a wand, a charged coupled device (CCD), or some other solid-state imaging device (SSI). Bar code reading systems are known in the art and have been disclosed, for example, in U.S. Pat. Nos. 4,251,798; 4,360,798; 4,369,361; 4,387,297; 4,409,470 and 4,460,120 and are incorporated by reference herein.
A number of different one-dimensional (1-D) bar code symbologies (encodation schemes) exist. These symbologies include UPC/EAN, Code 39, Code 128, Codabar and Interleaved 2 of 5. Due to their low information density storage capacity these types of bar codes can carry only a limited amount of information, on the order often to twenty letters or digits. This information is usually an index to a file or a database where more comprehensive information is stored.
Symbologies of (n,k) Type
Some bar codes are referred to as belonging to the (n,k) family. A code of (n,k) type uniquely represents characters by a string of n modules containing k bars and k spaces. The UPC symbology is an example of a (7,2) code, i.e., n=7 and k=2.
Two-dimensional (2-D) bar codes carry more information per substrate area than linear bar codes. Some two-dimensional bar code symbologies are just an extension of one-dimensional bar codes, in that they are formed by stacking rows of one-dimensional bar codes and typically placing a horizontal line between each row. In order to keep the same vertical dimension of the overall bar code, the height of each row is smaller then the normal height of a one-dimensional bar code. U.S. Pat. No. 4,794,239.
There exists a number of different two-dimensional code symbologies. Some of the symbologies are: Code49, 16K Code, Codabar, Supercode, Matrix code, etc. The PDF417 symbology is one type of two dimensional bar code symbology that is used when we need to encode a greater amount of information within a limited amount of space, thus giving us a higher information density encodation scheme. U.S. Pat. No. 5,304,786 which is incorporated by reference herein. A “stacked” two-dimensional bar code, such as PDF417, uses a row/column spatial arrangement of codewords. The information is usually broken up and encoded into individual “codewords” which, when decoded, are used to recompose the encoded information. PDF417 symbology has a number of variants. MicroPDF417 symbology is one of the variants of PDF417 symbology and is described in detail in AIM International Symbology Specification-MicroPDF417.
Composite Code
When two different symbologies are used to encode different parts of a given data, the resultant symbol is called a Composite code symbol. Thus, a composite symbol is a hybrid consisting of symbols encoded using more than one encoding scheme. For example, a product identification number may be encoded in a 1D bar code and supplementary product information may be encoded in a linked 2D bar code located adjacent the 1D bar code. Many companies would like to adopt Composite (1D/2D hybrid) symbologies, so that they can stay compatible with their installed base of 1D scanners (readers), and upgrade the scanning equipment over time (at their own pace) to also capture supplementary information (such as a serial number) in a linked 2D portion. For this to really work without disrupting the current application, the 1D barcode must remain compatible with “old generation” scanners, while adding an encoded “link flag” so that a “new generation” scanner knows that additional information is printed adjacent (above or below) the 1D bar code symbol. Without a link flag, a scanner (unless it captures a full two-dimensional 2D image) would decode the linear symbol and transmit the data from it, but fail to recognize that additional data was printed in an associated 2D symbol. A standard link flag has been defined for the 2D portion of a composite bar code symbol (for symbologies such as PDF417 and MicroPDF417), so the data encoded in the two-dimensional (2D) portion of a composite bar code won't accidentally be transmitted without the data in the accompanying one-dimensional (linear) bar code. But, linkage in both directions is needed, for a truly robust system.
In particular, UPC/EAN, Code 39, Codabar, and Interleaved 2 of 5 do not provide a means of adding a link flag character without changing the data that an old scanner would transmit.
An optical symbology is needed that provides the means for a code reader to recognize that a 1D code is a part of a composite symbol and that another part of the composite symbol must be adjacent to the 1D code, and that both 1D and 2D bar codes must be decoded in order to obtain full information contained within the composite symbol.
SUMMARY OF THE INVENTION
The present invention solves this problem by printing a link flag character outside of the linear barcode (preferably, immediately adjacent to its trailing white Quiet Zone). An old generation scanner would not decode this character (because it is outside the standard symbol), but a new generation scanner can be reprogrammed to look past the Quiet Zone for an additional character pattern. Different patterns could be assigned (and a list maintained by a standards organization such as AM) to represent different application data sets and rules, and/or to denote which 2D symbology (e.g., PDF417 vs. MicroPDF417) is linked to the accompanying linear symbol.
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Kirschstein et al.
Lee Michael G.
Nguyen Kim
Symbol Technologies Inc.
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