Optical patterning of multidomain liquid-crystal displays with wide viewing angles

THE leading technology for flat, high-resolution computer and television screens is based on twisted nematic liquid-crystal displays(1). The successful operation of these displays requires control of molecular alignment, which is currently achieved by confining the liquid crystal between mechanically rubbed surfaces(2). But in addition to the practical difficulties associated with rubbing, the resulting displays suffer from restricted viewing angles arising from the uniaxial nature of the alignment process(3,4). This latter problem can in principle be circumvented if molecular alignment is varied, in a controlled manner, within individual pixels(5-9). Exposure of functionalized substrates to polarized light offers a means of achieving high-resolution patterns in the plane of the display(10-12). But to ensure that the alignment pattern imposed on the liquid crystal is free of orientation defects, the tilt angle between the long molecular axes and the substrates must be precisely controlled(13-14). Here we show how our earlier linear photoalignment strategy(10,12) can be extended to obtain such control, and thereby fabricate stable, multi-domain pixel displays with markedly improved fields of view.