Abstract : This paper introduces the use of PLC, frequency converter, and touch screen to add a dust collection device to an automatic polarizer placement machine to improve the yield of polarizer placement. Keywords : PLC, frequency converter, touch screen, polarizer, placement 1. Necessity of Adding a Dust Collection System A typical liquid crystal display device consists of the following basic structures: upper polarizer, liquid crystal cell (front glass, sealing edge, rear glass), and lower polarizer. The polarizer, also known as a polarizing film, is made of plastic film material coated with a layer of optical pressure-sensitive adhesive, which can be attached to the surface of the liquid crystal cell. The liquid crystal cell consists of two layers of flat glass placed opposite each other, with a relative distance of 6-7 m between them. The manufacturing process of the liquid crystal cell in the middle and back stages is as follows: ① Cutting the large-size liquid crystal cell into the required small-size liquid crystal cells; ② Filling the liquid crystal cell with liquid crystal; ③ Sealing the filling port with sealant; ④ Chamfering the liquid crystal cell and then cleaning it; ⑤ Placing the polarizer; ⑥ Mounting various chips and flexible circuit boards; ⑦ Then assembling with the backlight, outer frame, etc. The most significant problem in the polarizer application process is foreign object defects, as excessively large fibers, glass shards, and other debris can exist between the polarizer and the liquid crystal cell. To remove foreign objects and dust from the surface of the liquid crystal cell before applying the upper and lower polarizers, two dust extraction mechanisms are added to the polarizer application machine, as shown in Figure 1. [b][align=center]For details, please click: Automatic Polarizer Application Device Dust Extraction System Added[/align][/b]