The Development History Of TFT LCD Screen

TFT LCDThe research on thin-film transistors can be traced back to the beginning of the last century. The concept and initial definition of field-effect transistors were proposed by German-American physicist Julius Edger Lilienfeld in 1925. In the 1940s, Bell Labs established a semiconductor research group. One of the areas of the group's work is the exploration of semiconductors and semiconductor-related technologies, such as making devices that can modulate current flow in semiconductor channels. In 1947, John Bardeen Walter H. Brattain, a member of Bell's semiconductor research group, successfully fabricated the point-contact transistor, a semiconductor amplifier used to amplify electrical signals. After that, William Shockley invented the bipolar transistor Bipolar Junction Transistor, BJT and Junction Field-Effect Transistor (JFET) based on the research of Bardeen and Brittan in early 1948. Three researchers were awarded the Nobel Prize in Physics in 1956 for their outstanding contributions to the field of semiconductors. Due to the limitations of the thin film transistor preparation process at that time, Weimer of the American Radio Corporation laboratory successfully prepared the first real thin film transistor using polycrystalline CdS film as the channel layer in 1962. The TFT device structure prepared by Weimer is a top gate bottom. Contact, choose to use SiO2 material as the TFT insulating layer, Au as the gate and source and drain electrodes, with glass as the substrate. In 1968, George Heilmeier of the RCA laboratory successfully developed the world's first Liquid Crystal Display (LCD), but the LCD panel still has some serious problems and cannot be directly put into operation. display field. At this time, the display method used on the control panel is an electrode cross-array display, and changing one pixel affects other adjacent cells, resulting in distortion and distortion of the image. In 1971, in order to effectively solve this technical problem, Lechner et al. first tried to combine TFT with LCD. The experiment started from the complexity of addressing circuit, lifespan and power consumption of the display, using a 2×18 liquid crystal display matrix to In the test, the intersections of the electrodes of the dot matrix display circuit are connected to the nonlinear circuit, the structure is composed of thin film transistors and capacitor units, and in addition to acting as a switch, it can also maintain the voltage of the pixel unit. Significantly improves the display quality of LCD panel images. Since then, TFT has shown its real commercial utility. Then, in the early 1970s, a brand-new electronic calculator developed and produced by Japan's Shengbao Company used the above-mentioned liquid crystal display panel for the first time, which greatly inspired researchers' enthusiasm for TFT research. Since then, TFT research has officially entered the stage. climax stage. [4]