15.3 An a-IGZO asynchronous delta-sigma modulator on foil achieving up to 43dB SNR and 40dB SNDR in 300Hz bandwidth

Amorphous IGZO (a-IGZO) TFTs fabricated on flexible large-area substrates provide better mobility than a-Si or organic counterparts and good uniformity. These features make a-IGZO TFTs an attractive technology for large-area sensing (e.g. strain, pressure, IR), low-cost RFIDs augmented with sensors and monitoring of biopotentials. In this context, it is crucial to accurately transform analogue sensor signals in a robust representation. The most common choice is a synchronous digital word, but a two-level PWM representation is another interesting possibility. Binary PWM can be transmitted on wire or via RF amplitude modulation with high immunity to noise and interferers

Low-cost monolithic processing of large-area ultrasound transducer arrays

Large-area flexible ultrasound arrays can offer new ultrasound modalities in multiple fields. The production of these arrays when using CMOS-type fabrication techniques faces scalability challenges and costs increase dramatically when upscaled to large dimensions. We investigate the monolithic production of large-area PPT (Printed Polymer Transducer) arrays directly on a flexible substrate. Here, a vibrating membrane is defined by a circular opening in a thick photoresist layer. Since the photoresist layer is processed on top of the P(VDF-TrFE), a thin barrier layer is used to prevent diffusion into the P(VDF-TrFE). An annealing procedure is developed to reduce the surface roughness of the P(VDF-TrFE) layer and make it compatible with thin film electrode deposition. We measure a remnant polarization of 7-8 μC/cm2 and a coercive field of around 50 MV/m. Laser scanning vibrometer measurements reveal a uniform peak displacement and fundamental resonance frequency (66 kHz) across the PPT array

Power saving through state retention in IGZO-TFT AMOLED displays for wearable applications

We present a qHD (960 × 540 with three sub-pixels) top-emitting active-matrix organic light-emitting diode display with a 340-ppi resolution using a self-aligned IGZO thin-film transistor backplane on polyimide foil with a humidity barrier. The back plane process flow is based on a seven-layer photolithography process with a CD = 4 μm. We implement a 2T1C pixel engine and use a commercial source driver IC made for low-temperature polycrystalline silicon. By using an IGZO thin-film transistor and leveraging the extremely low off current, we can switch off the power to the source and gate driver while maintaining the image unchanged for several minutes. We demonstrate that, depending on the image content, low-refresh operation yields reduction in power consumption of up to 50% compared with normal (continuous) operation. We show that with the further increase in resolution, the power saving through state retention will be even more significant