摘要 |
<p>The invention is an improved method and means for illuminating a liquid crystal cell (12) which provides a significant increase in the range of viewing angles in a plane orthogonal to the principal viewing plane which is defined as the plane containing the director (58) at the midpoint of the liquid crystal and the normal (52) to the light entry surface. The cell is illuminated by a beam which is substantially collimated in the principle viewing plane and substantially uncollimated in the orthogonal plane. Preferably, the thickness of the liquid crystal in the cell corresponds to the first Gooch-Tarry minimum. </p> |