Two-dimensional barcode/two-dimensional barcode (dimensional barcode) is a specific geometric pattern according to a certain law in the plane (two-dimensional direction) distribution of black and white graphic record data symbols information; in the code compilation on the clever use of the composition of the computer's internal logic, "0", the basis of the "0", the "0", the "0", the "0", the "0", the "0", the "0", the "0", the "0" and the "0". In the code compilation clever use of the internal logic of the computer constitutes the basis of the "0", "1" the concept of bit stream, the use of a number of geometric shapes corresponding to the binary to indicate the text numerical value information, through the image input equipment or photoelectric scanning equipment to realize the automatic processing of information automatic reading: it has the bar code technology Some **** sex: each code system has its own specific character set; each character occupies a certain width; with a certain checksum function. At the same time also has a different line of information on the automatic identification function, and to deal with graphic rotation changes and other characteristics. In many kinds of two-dimensional bar code, commonly used code system: Data Matrix, Maxi Code, Aztec, QR Code, Vericode, PDF417, Ultracode, Code 49, Code 16K, etc., QR code was invented by the Japanese Denso-Wave company in 1994. QR comes from the English "Quick Response" abbreviation. QR code comes from the abbreviation of English "Quick Response", that is, the meaning of quick response, from the inventor hopes that the QR code can make its content quickly be decoded. QR code is most commonly used in Japan, South Korea; and for the most popular two-dimensional space barcode in Japan at present.