IGZO is composite of indium (Id), gallium (Ga), zinc (Z) and oxygen (O). An IGZO-TFT is artificially produced and used in flat panel displays, which are made of transparent crystalline oxide semiconductors. This newly-invented IGZO-TFT enables LCD and OLED displays to achieve new levels of performance. Because of its attractive features, it is being used in ASUS notebooks, ultrabooks by Fujitsu and Razor Blade gaming laptops. Sharp mass produces it successfully. Low power consumption with high performance and high resolution are the key features of this technology.
Low power consumption with high performance. A comparison between the conventional display method and new display methods is shown in Fig. 3. The former consumes more power because all pixels are driven continuously. IGZO consumes less power for backlighting or illumination in LED panel as compared to a-Si.
There are a number of TFTs arranged in a particular structure which will switch on or off depending on the contents being displayed on the screen. If the static image or video content is being displayed using IGZO that operates in pause mode (as it is in this case), there will be less leakage current and no flicker effect, which results in low power consumption. Thus, in IGZO-TFT technology, pixels maintain their charge throughout the cycle, which results in low power consumption and flicker-less high performance.
High resolution. In IGZO-TFT, as shown in Fig. 4, transistor size is small as compared to a-Si-TFT. Because of that, more numbers of pixels per area can be accommodated as compared to a-Si, which enables high resolution. On top of this, IGZO has a much lower leakage current and 20 to 50 times higher electron mobility as compared to a-Si, which results in fast response time or less processing delay.
To summarise, new display techniques using quantum dots and IGZO have changed the entire world of displays, especially in television domain. Their extraordinary features enable these to consume low power, perform better, give HD colour resolution, and televisions to be made thinner, lighter and more energy efficient.
Dr Arjav Bavarva is assistant professor at Department of Electronics & Communication, School of Engineering, RK University, Gujarat. His research interest lies is electronics, wireless communication and networking.
Tejas Bavarva is ME in VLSI and embedded system design. He is currently working as senior systems engineer at Infosys Ltd, Pune. His interests include electronics, VLSI and networking.