QR code is a kind of two-dimensional bar code. QR comes from the abbreviation of "Quick Response" in English, which means quick response. It comes from the inventor's hope that the two-dimensional code can quickly decode its content. Two-dimensional code can store more data than ordinary bar code, and there is no need to arrange the scanner in a straight line like ordinary bar code. This QR code can be read quickly. Compared with previous barcodes, QR codes can store more information, including encrypted words, URL addresses and other types of data. Two-dimensional code 1994 was invented by Denso Wave Corporation of Japan. The two-dimensional code standard JIS X 05 10 was released in June 199 1, and its corresponding ISO international standard ISO/IEC 18004 was approved in June 2000. According to the website of Densovave, the QR code is an open standard, and the specifications of the QR code are open, and the patent rights held by Densovave will not be enforced. In addition to the standard two-dimensional code, there is also a format called "micro two-dimensional code", which is a reduced version of the two-dimensional code standard and is mainly designed for applications that cannot handle large-scale scanning. Micro QR codes also have various standards, and can store up to 35 characters.