Ryoichi Yokoyama

Development trends of LTPS TFT LCDs for mobile applications

Full integration of digital circuits will progress with increasingly minute design rules and higher mobility in TFT devices and improvement in processes. Together with improvements in circuit design technology, the low-temperature polysilicon (LTPS) TFT LCD is expected to be one of the most promising displays for digital tools such as cellular phones and PDAs, whose future market size is expected to expand by leaps and bounds. Moreover, improvements to minimize the scattering of the Vth of adjacent TFTs will bring about the integration of an op-amp and the further full-integration of analog/digital circuits on glass substrates.

22.1: Ultra-Low-Power Polysilicon AMLCD with Full Integration

An LTPS TFT LCD was developed that only consumes 0.07 mW of power. It is the worlds first LCD equipped with all the circuits needed to display static images continuously for up to one year on a button battery. At the same time, the panel is capable of displaying full-color moving pictures.

Ultra-low-power polysilicon AMLCD with full integration

An LTPS TFT-LCD that only consumes 0.07 mW of power was developed. It is the worlds first LCD equipped with all the circuits needed to display still images continuously for up to 1 year on a button battery. At the same time, the panel is capable of displaying 260,000-color moving pictures.

50.1: Invited Paper: Future Application Potential of Low Temperature p-Si TFT LCD Displays

As information technology rapidly grows, the development of LCDs with higher specifications is demanded for use as information display devices. Since the LTPS TFT enables high performance circuit integration in the LCD, it is a suitable technology for mobile information devices. Here we will discuss past and present LTPS TFT LCD circuit design technologies, devices and processes technologies, and will propose a next-generation LTPS TFT LCD technology road map.

27.5: New Dot-Inversion Driving Method for Low Power Consumption LTPS TFT LCDs

We have developed a new dot-inversion driving method for low-power-consumption LTPS TFT LCDs. This driving method realizes as much as a 50% reduction in power consumption as compared to the common-electrode AC driving method commonly used in conventional low power consumption LCDs. Since the method achieves high resolution and high image quality, it is also suited for use in LCDs for mobile applications.