TFTbackplane

TFT backplane is the active-matrix driving layer in most modern flat-panel displays, providing the addressing circuitry for each pixel. It consists of an array of thin-film transistors and storage capacitors fabricated on a substrate, typically glass, but also flexible plastics in some designs. Each pixel is addressed via gate and data lines, with a transistor at the pixel controlling the voltage applied to the pixel electrode and a storage capacitor holding that voltage between refresh cycles. This arrangement enables precise, independent control of millions of subpixels.

The backplane materials have evolved to balance performance, cost, and manufacturing compatibility. Amorphous silicon (a-Si) was common in earlier LCDs, while higher-mobility options such as low-temperature polycrystalline silicon (LTPS) and oxide semiconductors like IGZO are increasingly used for higher resolution, faster switching, and reduced leakage. The backplane is typically fabricated on a transparent or clear substrate and is combined with other layers in the display stack, with some flexible versions using plastic substrates.

Applications include active-matrix LCDs, OLED and AMOLED displays, and other flat-panel technologies. In OLED displays, the TFT backplane provides current-driving transistors for each subpixel; in LCDs, it controls the voltage applied to the liquid crystal to modulate light transmission. Common backplane architectures use one transistor and one capacitor per pixel (1T1C) with various addressing schemes to optimize performance, power, and cell aperture.

Manufacturing challenges encompass achieving uniform transistor characteristics, minimizing leakage and parasitic effects, maximizing aperture ratio, and ensuring reliability across temperature variations and long-term use.