On the most popular digital image four electronic

2022-07-23
  • Detail

Talking about digital image (IV) -- Introduction to electronic image sensor. It turns out that electronic image can be traced back to 1873. At that time, scientists Joseph may and willoughbysmith discovered that selenium crystal can generate current after photosensitization, which is the beginning of the development of electronic image. Since then, organizations and scholars have successively studied electronic images, among which the important inventions are television system, photomultiplier tube (PMT) and charge. Coupled device (CCD)

Figure 1: electronic image sensors are very common. For many office and home electronic products, PMT and CCD are very successful electronic image sensors (also known as optical sensors). The former was invented in the 1950s, and the latter was invented in the 1970s. They can be applied to a variety of products, such as astronomical telescopes Disc satellite (some foreign companies provide satellite digital photo services, which can take photos of any corner of the world for about 300 Hong Kong dollars), thermometer, analyzer, fax machine and scanner. CCD can also be used in small products such as digital cameras and portable video recorders. In 1998, two new types of electronic image sensors emerged, namely, CMOS (completionarymetal oxide semiconductor) and CIS (contact lmage sensor). Then their technical and commercial applications are introduced. Electronic image sensor

(electronic image sensor)

in the past, the astronomical telescopes of the U.S. Observatory used film to take images. Later, the electronic image sensor replaced film, which not only avoided the printing process and can be immediately displayed on the screen, but also has much stronger photosensitivity than film. After connecting to the computer, digital technology can be used to improve the image quality. From the 1950s to the present, electronic image sensors have been widely used in commercial applications, such as satellite digital photos mentioned earlier, astronomical telescopes that shoot the universe from the ground, and digital photo selfies used by young people in shopping malls in life and entertainment. Of course, the most common applications are fax machines, scanners, digital cameras and portable video recorders

Figure 2: hammatsu R980 PMT optical multiplier tube PMT -- from 1950s. It is the earliest electronic sensor and the best (quality) technology at present. The structure is like a small cylindrical bulb (see Figure), with a length of about two inches and a diameter of about one inch. It has built-in multiple electrodes to convert the incoming light into a powerful electronic signal. Even a very weak light can be accurately captured, which is superior to other sensors. PMT is often used in scanners and engineering analyzers in printing and publishing industries. The highest sensing density of the PMT scanner can reach D4.2, indicating that it can capture very dark image parts on the original. PMT is very durable, and generally has one to 100000 operating hours

Figure 3: single line CCD chip, used for black-and-white scanners (color scanners use three line C to open the CD chip of the control computer (or controller), while digital cameras or video recorders use plane () two-dimensional CCD chip). CCD was invented by Bell Laboratories in 1969. Similar to the CMOS technology of computer chips, it can also be used as computer memory and logic operation chips. Of course, DRAM is more suitable for electronic memory at present. The most popular applications are scanners, digital cameras and hand-held video cameras. However, the most striking work is to install four large CCD chips in the BTC (big throughput camera, see Figure 5) astronomical telescope of the andas American Observatory in Chile, South America. It can take 35MB of data at a time, which greatly helps astronomical research. The photosensitivity and quality of CCD are lower than that of PMT. However, in recent years, the CCD technology has made progress. Its highest density can reach d4.0, which is slightly lower than the highest induction window of PMT. Volume of CCD. It is usually as big as an ordinary coin. Of course, there are some very large (see Figure 4) or small ones. CCD is as durable as PMT

Figure 4: Tony Tyson, a researcher at Bell Laboratories, uses the CCD in his hand to conduct astronomical research. Copyright of Bell Labs, Lucent Technologies Figure 5: the four meter long BTC astronomical telescope located in the InterAmerican Observatory in Chile has four bell large CCD chips placed at its tail end. Copyright of Bell Labs, Lucent Technologies Figure 6: a cosmic jigsaw shot by BTC astronomical telescope

copy of Bell Labs, Lucent Technologies CMOS -- this technology has been developed for decades. It can be said that digital computers have it, because CPU and memory are composed of CMOS. However, it was only applied to electronic sensors or digital cameras in 1998. It can also be applied to video cameras. The advantage of CMOS is that its structure is simpler than that of CCD, making energy saving and material saving the focus of extrusion processing industry. With smaller crystal and lower voltage, the manufacturing cost is lower than that of CCD. CMOS also has its disadvantages, that is, the technology is not mature, the quality is generally lower than that of CCD, and the resolution is generally poor. However, according to the data, the asphalt based carbon fiber market in 2014 was 15.3 billion yen (about 800million yuan), indicating that the technology of CMOS (refer to the address not provided in this article) will progress and surpass CCD

Figure 7: CIS structure diagram cis - due to the structural relationship, CIS technology is usually only used for scanners. The inductor is CMOS. The CIS scanner fixes the light source, focusing lens and inductor together in a housing without adjusting and warming up, so it starts faster than the tester detector of the CCD scanning plastic film impact strength tester. The size of CIS scanner is smaller than that of CCD scanner, and the manufacturing cost is reduced. However, the C1s technology is not mature and produces large noise, so it is inferior to CCD at present. Summary

pmt, CCD, CMOS and CIS are currently popular electronic image sensors. The manufacturing of PMT and CCD is complex and costly. A sensor needs tens to hundreds of dollars, but the quality is also good. Especially, the quality of PMT is the highest. The professional roller scanner uses PMT technology, but its volume and structure are not suitable for portable or small products. CCD, CMOS and CIS are small in size and can be used in small products. At present, most electronic imaging products use CCD. It is hoped that there will be more products of other electronic imaging technologies (such as CMOS or better sensors) in the near future, so that consumers can have more choices

reference

Copyright © 2011 JIN SHI