Working Principle: The light pen is one of the first handheld contact barcode readers. When used, the operator needs to touch the light pen to the barcode surface. Through the lens of the light pen sends out a very small point of light, when this point of light from left to right across the bar code, in the "empty" part, the light is reflected, the "bar" part, the light will be absorbed, so in the internal light pen to produce a change in the voltage, this voltage is amplified, shaped and used for decoding. This voltage is amplified and shaped for decoding.
Classification:
Two-dimensional barcode scanners can be broadly divided into: handheld, fixed.
1, handheld: that is, two-dimensional code scanner gun. Can scan PDF417, QR code, DM code two-dimensional barcode scanner, such as Symbol's DS6707.DS6708 and so on.
2, fixed: that is, two-dimensional code reader, desktop, non-handheld, on the table or fixed in the terminal equipment, such as SUMLUNG's SL-QC15S and so on.
Expanded Information:
Laser scanners can be used for non-contact scanning, usually, in the reading distance of more than 30cm when the laser reader is the only choice; laser reading barcode density range, and can read irregular barcode surface or read through the glass or transparent adhesive paper, because it is non-contact reading.
So it will not damage the bar code label; because there are more advanced reading and decoding system, the first reading recognition success rate is high, the recognition speed relative to the light pen and CCD faster, but also on the printing quality is not good or fuzzy bar code recognition effect is good; BER is very low (only about one in three million); laser reader shockproof and drop-proof performance is good, such as: SymbolLS4000 series of scanners, can be 1.5 meters of cement floor anti-drop performance, such as: SymbolLS4000 series scanner. Can be 1.5 meters of concrete fall.
Baidu Encyclopedia - Barcode Scanner