Know about the barcode
Bar code technology first developed in the horrible 20 s, was born in the lab, Westinghouse.A man named John Kermode was eccentric inventor "fantasy" to realize automatic sorting for postal document, at the time of every vision electronic technology application make the person feels very novel.
His idea is to do the barcode tag on the envelope, the information in the barcode is the recipients address, just like todays zip code.Therefore Kermode invented the first bar code identification, design is very simple (note: this method is called module comparison method), that is, a "article" number "1", said two "a" number "2", etc.Then he invented the barcode reading equipment is composed of basic elements: a scanner (can launch and receive light reflected light);A determination of reflected signal bar and empty methods, namely, the coil edge positioning;And the method of using the determination results, namely the decoder.
Kermode scanner using the new invention of photocell to collect reflected light."Empty" is reflected in the strong signal, "article" is reflected in the weak signal.With todays high-speed electronic elements are used for different Kermode using a magnetic coil to measure "article" and "empty".Like a child will wire connected to the battery again around a nail up a paper.Kermode iron core coil with a belt when receives the "empty" to attract a switch, when receives the "article", the release of switch and connect circuits.Therefore, the earliest barcode reader disturbing noise.Switch consists of a series of relay control, "on" and "off" by the number of print on the envelope "article" decision.In this way, bar code directly to sorting the mail.
Shortly thereafter, Kermode collaborators Douglas Young, on the basis of the Kermode code made some improvements.
Kermode code contains the amount of information is quite low, and it is difficult to make up more than ten different code.Article and Young code to use fewer, but between the article use the empty size changes, just like todays article UPC barcode symbol using four different size.New bar code can be in the same size coding space of one hundred different areas, and Kermode code only encodes ten different areas.
Until the patent literature in 1949 for the first time, have been the Norm of Woodland and Bernard Silver of the full range of bar code symbol invention records, before this has not bar code technology in the patent document records, nor in the actual application of precedent.Norm of Woodland and Bemard the idea is to use Silver Kermode and YOung vertical "article" and "empty", and make it bent into a ring, very like archery target.So the center of the scanner to scan graphics, able to bar code decoding, regardless of the direction toward the bar code symbol.
In this patent technology is used to the process of continuous improvement, a science fiction writer Isaac - Azimov in his book "exposed the sun" tells the story of new information encoding method is used to realize automatic identification.When people think of the book of the bar code symbol looks like a square grid board, but todays barcode professionals will soon realized that this is a two dimensional matrix notation.Although this bar code symbols have no direction, positioning and timing, but apparently it represents high information density digital coding.
Until 1970 Iterface Mechanisms company developed the "qr code", is the price is suitable for sales of two-dimensional matrix bar code printing and read equipment.It was two dimensional matrix used in newspaper publishing process automation.Bar code printing on paper tape, two-dimensional matrix by one dimensional CCD scanners scan read today.The CCD light on the tape, each cell on different areas of the tape.Each cell according to the different patterns of printing on paper tape barcode or not output, combined to create a high density information design.In this way can be in the same space to print the size of a single character, as an early Kermode code in a single article.Timing information is also included, so the process is reasonable.When the first system after entering the market, a full set of equipment, including print and read the equipment would be about $5000.
Shortly thereafter, as the LED (light-emitting diode), microprocessor and the continuous development of the laser diode, welcomed the new identity symbol (symbol) and its application of the big bang, people call it "barcode industry".Are seldom found today had no direct contact with the fast and accurate of bar code technology companies or individuals.Due to technical progress and development in this field is very rapid, and every day, more and more application fields were developed, it wont be long before the barcode will be like a light bulb and the transistor radio popularization, will make our each persons life becomes more easy and convenient.
Bar code is composed of a set in a certain encoding rules permutation, empty symbols, to a certain information of characters, Numbers and symbols.Bar code system is composed of bar code design, production and scanning reading of automatic identification system.