QR Code
Designed by Denso Wave in Japan for the automotive industry in 1998, Quick Response (QR) Code is a two-dimensional general-purpose matrix barcode that is intended for use on smaller labels. It was designed for faster scanning of information, and it efficiently encodes kanji characters.
QR Code can be printed in black on a white background or in white on a black background.
Several versions of QR Code have evolved over the years as technology improves. QR Code Model 1 was the first version, followed by QR Code Model 2. Currently, QR Code 2005 is the standard version that is recommended for new applications.
QR Code is defined in ISO/IEC 18004 Information technology - Automatic identification and data capture techniques - QR Code 2005 bar code symbology specification.
The symbol comprises the following elements:
Data is stored in "modules" (square dots) in the data area as binary information. Each black module represents a binary 1, and each white module represents a binary 0.
The finder patterns are the square bull's eyes that appear in three corners of the symbol. These patterns enable the barcode to be scanned correctly at any orientation.
The alignment pattern, which is present only in version 2 and larger symbols, helps the decoding software re-synchronize in case of slight distortion of the code. It consists of a grid of small square bull's eyes that is overlaid over the data region.
The timing patterns consist of one row and one column of alternating black and white modules. They enable the reader to determine symbol version and density.
This symbology supports the following characters in the following modes:
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Numeric mode: Includes all numeric digits (0-9)
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Alphanumeric mode: Includes all numeric digits (0-9), uppercase letters (A-Z), and the following special characters:
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Dollar sign ($)
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Percent sign (%)
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Asterisk (*)
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Plus sign (+)
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Hyphen (-)
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Period (.)
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Slash mark (/)
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Colon (:)
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Space character
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Byte mode: Includes data that is encoded at 8 bits per character; the default character set is as defined in ISO/IEC 8859 Information technology - 8-bit single-byte coded graphic character sets
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Kanji mode: Includes kanji characters that are encoded in accordance with the Shift JIS system as defined in Japanese Industrial Standard (JIS) X 0208 7-bit and 8-bit double byte coded KANJI sets for information interchange; the following values are supported:
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8140HEX–9FFCHEX
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E040HEX–EAA4HEX
For more information about kanji mode, see JIS X 0208 Annex 1: "Shift Coded Representation."
It is possible to manually switch between modes in a single barcode.
QR Code uses the Reed-Solomon algorithm for error correction. Four selectable levels of error correction are available, which enables the barcode to be read even if up to 30 percent of the code is damaged.
QR Code has 40 possible sizes, referred to as version 1, version 2, and so on through version 40. Version 1 (the smallest) is 21 x 21 modules, and version 40 (the largest) is 177 x 177 modules.
The minimum quiet zone on all sides is the equivalent of four modules.
Symbol Structure