Optimisation of very small pitch active matrix LCD for projection

AM LCDs (liquid crystal displays) with <100- mu m pitches are capable of EDTV/HDTV (enhanced-definition/high-definition TV) projection, but these pitches imply electrical parasitic effects and small aperture ratio. A structure combining a storage capacitor and a black matrix with an 85- mu m pitch is evaluated and experimental results are presented. It is shown that the ground-plane-type storage capacitor is very efficient for designing low-pitch AM LCDs for projection since it reduces the many couplings of the cell. Moreover, a black matrix can easily be designed on that ground plane, which helps to keep a high OAR (open aperture ratio): a 85- mu m-pitch cell with a >60% OAR has been achieved thanks to this design.<>