Reading principle of CCD barcode scanner

CCD is an electronically coupled device (Chargcoupledevice), which is more suitable for close range and contact reading. Its price is not as expensive as a laser reader, and there are no moving parts inside.

The CCD reader uses one or more LEDs, and the light emitted can cover the entire barcode. The image of the barcode is transmitted to a row of light, sampled by each individual photodiode, and the neighboring detection result is "black" or " "White" distinguishes each bar or space, so as to determine the characters of the bar code. In other words, the CCD reader does not pay attention to reading each "bar" or "space", but the entire part of the bar code and converts it into an electrical signal that can be decoded. .

Advantages: Compared with other readers, CCD readers are cheaper, but they also have a wide range of reading densities and are easy to use. It's lighter than a laser reader, and unlike a light pen, it can only touch and read.

Disadvantages: The limitation of the CCD reader lies in its reading depth of field and reading width. It will be difficult to read the barcode printed on the curved surface (such as a beverage can). In some occasions that require long-distance reading, such as in the warehouse field, Not very suitable; CCD's anti-fall performance is poor, so the failure rate is high; when the barcode to be read is relatively wide, CCD is not a good choice, and the barcode with long information or low density is easy to exceed the scanning The reading range of the head makes the bar code unreadable; and in some bar code readers that use multiple LEDs, any one of the LEDs will fail to read; most CCD readers have a low first read success rate and a high probability of error.