Due to the limitation of the display principle of TN-LCD and STN-LCD, if the LCD display part becomes larger and larger, the electrode reaction time of the central part may also be correspondingly longer. In fact, for small screens, this is not a big problem. For example, the current mobile phone display screen is relatively small, and the impact of the liquid crystal response time is relatively small. However, for notebook computers, LCD industrial display screens and other devices that require large-screen LCD display, too slow LCD response time will seriously affect the display effect. Therefore, TFT-LCD technology has attracted the attention of manufacturers. In addition, with the increasing use of color screens. In the new-generation products, many support 65536 colors, and some even support 160,000 colors. At this time, TFT has the advantages of high contrast and rich colors
STN liquid crystal is a reflective LCD device, which has the advantage of low power consumption, but its definition is poor in a dark environment, so it must be equipped with an external light source. TFT liquid crystal adopts a combination of "rear transmission" and "reflection", and a special light pipe is set on the back of the liquid crystal. This is why we can see that some displays seem to have a "light" next to them, and some of the display's light seems to come from the display itself. In addition, LCD backlight technology is also constantly improving, from monochrome to color, from thick to thin, from side fluorescent lamps to flat fluorescent lamps.
By the way, there are two types of reflective liquid crystal display devices: white characters on a black background &40;NB&41; black characters on a white background &40;NN&41. The V70 display we see belongs to the NB type. Of course, this is definitely an enhanced NB that incorporates new technologies. Okay, back to the beginning of the topic, continue to discuss the display principle of TFT LCD. TFT liquid crystal display technology is driven by "active matrix". This method uses transistor electrodes made of thin film technology and a scanning method to "actively" control the opening and closing of any display point. When the light source is illuminated, it first passes through the lower polarizer and transmits light through the liquid crystal molecules. When the electrodes are opened, the arrangement of the liquid crystal molecules is similar to that of TN liquid crystals & 41; displays through shadows and light transmission. It sounds a lot like the display principle of TN liquid crystal, that's right. However, due to the capacitance effect of the FET transistor, it can maintain a potential state, and the transparent liquid crystal molecules will remain in this state until the FET electrode is energized again to change its arrangement. TN type liquid crystal does not have this characteristic.
Once no electric field is applied, the liquid crystal molecules will immediately return to their original state. This is the difference between TFT liquid crystal and TN liquid crystal in the display principle.
Each pixel of TFT LCD has a semiconductor switch, and its processing technology is similar to a large-scale integrated circuit. Because each pixel can be directly controlled by dot pulses, each node is relatively independent and can be controlled continuously. This design not only improves the response speed of the display screen, but also accurately controls the display gray level, making the display color of the TFT-LCD more realistic.
