![]() ![]() China led color pixel factory skin#People are the largest source of particles, from shedding dead skin cells, dust from cosmetic powders, or smoke particles exhaled from the lungs of workers who smoke. Workers have to wear special clean room protective clothing and scrub before entering to minimize dust particles or other contamination. That means the air is passed through elaborate filtration systems and pushed downwards from the ceiling constantly. Any dust particles in the air could cause defects in the finished displays – tiny dark spots or uneven intensities on your screen. LCD fabs have to maintain strict standards of cleanliness inside. That’s one way to recognize an LCD fab from the outside – loading docks on high floors that just open to the outdoors. When they bring the manufacturing equipment in, they load it onto a platform and hoist it with a crane on the outside of the building. Since the equipment floor is usually one or two stories up, there are large loading docks on the outside of the building. I visited a Gen 5 fab in Taiwan in 2003, and the plant manager there told me they used three times as much structural steel as Taipei 101, which was the world’s tallest building from 2004- 2010. The main equipment floor has to provide a very stable environment with no vibrations, so an LCD fab typically uses far more structural steel in its construction than a typical skyscraper. The main equipment floor is sandwiched between a ground floor that is filled with chemical pipelines, power distribution, and air handling equipment, and a third floor that also has a lot of air handling and other mechanical equipment. The fab is enormous, 1.3 km from one end to the other, divided into three large buildings connected by bridges. If you wanted to make 110 inch TVs, you could make two of them at a time. The Hefei Gen 10.5 fab is designed to produce the panels for either eight 65 inch or six 75 inch TVs on a single mother glass. The sheets of glass are only 0.5 - 0.7 mm thick or sometimes even thinner, so as you can imagine they are extremely fragile and can really only be handled by robots. ![]() The first modern LCD Fabs built in the early 1990s made sheets the size of a single notebook computer screen, and the size grew over time. The sandwich is next covered with special sheets of polarizing film, and the sheets are cut into individual “panels” – a term that is used to describe the subassembly that actually goes into a TV.įor the sake of efficiency, you would like to make as many panels on a sheet as possible, within the practical limitations of how big a sheet you can handle at a time. You have to align the two sheets so the colored dots sit right on top of the cells, and you can’t be off by more than a few microns in each direction anywhere on the sheet. Then you drop tiny amounts of liquid crystal material into the cells on the first sheet and glue the two sheets together. This is how you produce the colors when you shine light through it. On the other sheet of glass, you make an array of millions of red, green, and blue dots in a black matrix, called a color filter array (CFA). Remember, the average human hair is 40 microns in diameter. Each step has to be precisely aligned to the previous one within a few microns. This patterning step is repeated to build up tiny little cells, one for each dot (known as a pixel) on the screen. Then you deposit a layer of silicon, followed by a process that builds millions of precisely shaped transistor parts. ![]() That’s how you can get electrical signals to the middle of a screen. On one of the sheets are transistor “cells” formed by first depositing a layer of indium tin oxide (ITO), an unusual metal alloy that you can actually see through. ![]() Liquid crystal display (LCD) screens are manufactured by assembling a sandwich of two thin sheets of glass. BOE has a total of 12 fabs in Beijing, Chongqing, and several other major cities across China this particular factory was named Fab 9. This was the third factory, or “fab” that Beijing-based BOE built in Hefei alone, and in terms of capability, it is now the most advanced in the world. Last week I had the opportunity to tour BOE Technology Group’s Gen 10.5 factory in Hefei, the capital of China’s Anhui Province. ![]()
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