Patent ID: 7663712
Filing Date: 2010-02-16
Classification: G02B,G02F

Abstract:
1. A display apparatus comprising: a) a light source; b) a light guiding plate for transmitting light from the light source outward from a two-dimensional light-providing surface, one dimension of the light-providing surface defined in a width direction parallel to the path of incident light from the light source and the other dimension of the light-providing surface defined in a length direction, orthogonal to the width direction; c) a linear divergence reduction surface for reducing the divergence of light from the light providing surface predominantly with respect to the width direction, to provide a linearly divergence-reduced illumination, whereby divergence along the width direction at full-width half-maximum is less than about 50% of divergence at full-width half-maximum along the length direction; d) a liquid crystal display component for modulating the linearly divergence-reduced light to form a modulated light according to image data, and, e) a diffusing surface in the path of the modulated light; wherein the linear divergence reduction surface comprises a film substrate featured with a plurality of light divergence reduction structures, wherein each light divergence reduction structure is longitudinally extended in the length direction along the light-providing surface, each light divergence reduction structure comprising: (a) an input aperture optically coupled to the light-providing surface; (b) an output aperture distal from said input aperture, wherein the output aperture has a surface area that is larger than the surface area of the input aperture and the width of the output aperture varies over the length of the light divergence reduction structure; and, (c) a pair of curved side walls between the output aperture and the input aperture and extending along the length direction; wherein, in a cross section taken orthogonally with respect to the width direction, the curved side walls approximate a parabolic curvature.