What are the differences between CMOS and CCD industrial barcode scanner

  1. The imaging process. CCD and CMOS industrial barcode scanner image sensor have the same principle of photoelectric conversion, their main difference is that the signal readout process is different; Since CCD has only one (or a few) output nodes to read uniformly, the consistency of its signal output is very good; In CMOS chip, each pixel has its own signal amplifier to perform charge voltage conversion, and its signal output consistency is poor. However, in order to read the whole image signal, CCD requires a wide bandwidth of the output amplifier. In CMOS chips, the bandwidth of the amplifier in each pixel is low, which greatly reduces the power consumption of the chip. This is the main reason why CMOS chips have lower power consumption than CCD chips. Although the power consumption is reduced, the inconsistency of millions of amplifiers brings higher fixed noise, which is the inherent disadvantage of CMOS industrial barcode scanners compared with CCD.

  2. Integration. From the perspective of manufacturing process, the circuits and devices in CCD are integrated in semiconductor single crystal material, the process is complex. Only a few manufacturers in the world can produce CCD wafers, such as DALSA, SONY, Panasonic, etc. CCD can only output analog electrical signals, which need to be processed by the subsequent address decoder, analog converter, image signal processor and also need to provide three groups of power supply synchronous clock control circuits with different voltages, so the integration is very low. CMOS is integrated on the sheet monomer material called metal oxide. This process is the same as the process of producing tens of thousands of computer chips, storage devices and other semiconductor integrated circuits. Therefore, the cost of sound field CMOS industrial barcode scanners is much lower than that of CCD. At the same time, CMOS chip can integrate image signal amplifier, signal reading circuit, A/D conversion circuit, image signal processor and controller into one chip. Only one chip can realize all the basic functions of the barcode scanner with high integration. The concept of chip level barcode scanner is generated from this. With the continuous development of CMOS industrial barcode scanner imaging technology, more and more companies can provide high-quality CMOS imaging chips, including Micron, CMOS IS, Cypress, etc.

  3. Speed. CCD adopts photosensitive output one by one, which can only be output according to the specified program and the speed is slow. CMOS is controlled by multiple charge voltage converters and row column switches, so the readout speed is much faster. At present, most high-speed barcode scanners above 500 fps are CMOS industrial barcode scanners. In addition, CMOS address gating switch can sample randomly to achieve sub window output, which can achieve higher speed when only sub window images are output.

  4. Noise. CCD technology has been developed earlier. PN junction or silicon dioxide (SiO2) isolation layer is used to isolate noise. The imaging quality has certain advantages over CMOS photoelectric sensor. Due to the high integration of CMOS industrial barcode scanner image sensor, the close distance between each component circuit causes serious interference, and the noise has a great impact on the image quality. In recent years, with the continuous development of CMOS circuit noise elimination technology, it provides a good condition for the production of high-density and high-quality CMOS industrial barcode scanner image sensors.

FV105 series is one model of infoscan's Industrial Barcode Scanner with 1.2 megapixel High Performance CMOS sensor, multiple lighting units with powerful image processing and decoding algorithm. In the face of challenging application scenarios such as high-speed and high-frequency reading, high-density barcode reading and DPM barcode reading, FV105 can provide users with better reading and operation experiences.

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