Digital Driving Method for Low Frame Frequency and 256 Gray Scales in Liquid Crystal on Silicon Panels

A liquid crystal on silicon (LCoS) panel for projector applications is developed using a new digital driving method to increase the gray scale of the projected image without increasing the driving frequency. The LCoS panel, which has a wide video graphics array (WVGA) resolution, is fabricated using 0.18 μm CMOS process technology with an area of 9600 μm × 5800 μm. The projection system is successfully demonstrated using the fabricated LCoS panel and the proposed digital driving method. The measured results of the projection system show that the proposed driving method achieves an 8-bit gray scale at a driving frequency of 75.6 MHz, which is less than 13.7% of the frequency in previously reported methods such as frame rate control and pulse width modulation.