A 0.37-in. 5900PPI liquid crystal on silicon CMOS SoC using low voltage high dynamic voltage range novel pixel circuit for augmented reality micro-displays

A new pixel circuit and a driving circuit are proposed for high-resolution field sequential color driven liquid crystal on silicon (LCoS) micro-displays. The proposed pixel circuit is based on data storage with global charge transfer, whose reference node is controlled to increase the LC node voltage and to decrease the response time. Pixel LC reference node voltage modulation is adopted to reduce the pixel size and the driving circuit operation voltage by half. This allows the pixel display to be operated with an overdrive scheme, at low-voltages and a wide dynamic range. As a result, the pixel driving circuits and the pixel circuit achieve low-color crosstalk, and both power consumption and area are greatly reduced. To verify proper operation of the proposed pixel circuit, a 0.37-in. 360-Hz field refresh rate full-HD video resolution 5900PPI 4.3-μm pixel pitch backplane is implemented in 0.11-μm CMOS technology using 1.5- and 6-V supplies for logic and pixel driving, respectively. Measurement results demonstrate that the LC voltage dynamic range and the maximum brightness are increased by as much as 1.4 V and 39.7%, respectively. The response time is also reduced by approximately 30% owing to the proposed unique overdriving scheme.