Bar Code Scanner Four Technologies

Bar Code Scanner Four Technologies

Good quality bar code reader usually uses the following four technologies: light pen, CCD, laser, image red light.
Light pen is the first hand contact bar code reader, it is also the most economical bar code reader. When used, the operator should be light pen come into contact with the surface of the bar code, through the lens of the light pen making a very small points of light, when the light from left to right across the bar code, in the "empty" section, the light is reflected, part of the article "the", the light will be absorbed, so in the light pen produces a change in voltage, the voltage after amplification, plastic used for decoding.
The advantage is to contact with the bar code reading, can be clear which is the bar code to be read; The length of reading bar codes can be unlimited; Compared with other reader cost is low; No moving parts inside, relatively strong; Small in size and light in weight. Disadvantages: the use of light pen will be subject to various restrictions, such as in some occasions is not suitable for contact reading bar code; In addition, only on a relatively flat surface to read the specified density, the printing quality of the bar code, light pen can play its role; And operators need to be trained to use, such as reading speed, reading Angle, and the use of improper pressure will affect its reading performance; Finally, because it must be read in contact, light pens should not be used when the bar code is damaged due to improper storage or when there is a protective film on it. Light pen has low first read success rate and high bit error rate.

CCD is an electronic coupler, more suitable for close and contact reading, its price is not as expensive as the laser reader, and there are no moving parts inside.
The CCD reader uses one or more leds, which emit light that can cover the entire bar code. The image of the bar code is transmitted to a row of light and sampled by each individual photodiode. Each bar or blank is distinguished by the detection result of the adjacent "black" or "white", thus determining the character of the bar code. The CCD reader is not paying attention to read every "bar" or "empty", but the whole part of the bar code, and converted into an electrical signal that can be decoded.
The advantage is that compared with other readers, the price of CCD reader is cheaper, but also has the density of reading bar code wide, easy to use. It weighs less than a laser reader and is not touch-only like a light pen. The disadvantage is that the limitation of the CCD reader is its reading depth and reading width, and it will be difficult to read the bar code printed on the arc surface (such as beverage cans). It is also not suitable for some remote reading occasions, such as warehouse area; The crash resistance of CCD is poor, so the failure rate is high. When the bar code to be read is relatively wide, CCD is not a good choice, the bar code with very long information or very low density is easily beyond the reading range of the scanning head, resulting in the bar code is unreadable; And some take more than one LED bar code reader, any LED failure will lead to can not read; Most of the good quality CCD readers have low success rate of first reading and high error rate.
Principle of laser gun

Laser scanner is a relatively high price among all kinds of scanners, but it can provide the highest functional indicators, so it has been widely used in various industries.
Good quality the basic working principle of laser scanner for hand-held laser scanner through a laser diode with a beam of light, exposure to a rotating prism or back and forth on the mirror, the reflection of light through the exposure to the surface of the bar code reading window, the light through the reflex of the bar or empty return to reader, consists of a collection, focusing mirror, It is converted into an electrical signal by a photoelectric converter, which is then decoded by a scanner or a decoding software on the terminal.
Laser scanner is divided into two forms of handheld and fixed: handheld laser gun connection is convenient and simple, flexible use, fixed laser scanner is suitable for reading the largest, small bar code occasions, effectively free hands to work.
The advantage is that laser scanners can be excellent for non-contact scanning. In general, laser readers are the only option when the reading distance is over 30cm. Laser reading bar code has a wide density range, and can read irregular bar code surface or through glass or cellophone paper reading, because it is non-contact reading, so it will not damage the bar code label; Because of the more advanced reading and decoding system, the first reading recognition success rate is high, the recognition speed is faster than the light pen and CCD, and the printing quality is not good or fuzzy bar code recognition effect is good; The bit error rate is extremely low (only about 1 in 3 million); The laser reader is shock-proof and tumor-proof. The disadvantage is that the only drawback of laser scanner is its relatively high price, but if calculated from the sum of purchase cost and use cost, and CCD reader is not too much different.
Image red light
The image-type red Barcode Reader is a barcode reader that can replace the laser gun. Its scanning depth of field is up to 30cm, and its scanning speed is up to 300 times/second, so that it has excellent reading performance. The UNIQUE IMAGE DESIGN MAKES THE DECODING ABILITY VERY strong. The barcode cannot be read by ordinary scanners, but the image red light can still read easily. Through the intelligent interface, it only needs to replace the cable to realize the conversion of keyboard, RS232 serial port, USB and other interfaces. At the same time, it can also connect the laptop directly. For special devices such as handheld computers, some models can be directly powered by built-in batteries, which solves the problem of insufficient power supply capacity of handheld computers. It can also be set up and upgraded by software. The rich data editing function can make the image-based red light scanner fully cooperate with the user's existing software.