Photoalignment Method for LCD Transmittance via Oblique UV Exposure

The patent applies different exposure directions to different regions of the substrate. Specifically, the first region is exposed in a first direction, the second region in a second direction, the third region in a third direction, and the fourth region in a fourth direction. This local differentiation of exposure quality prevents the formation of uniform alignment dark patterns across the pixel, thereby improving local transmittance while maintaining overall alignment quality.

The patent introduces asymmetric exposure directions rather than symmetric perpendicular directions. The exposure directions are designed with specific angular relationships (first angle and second angle relative to reference directions) that break the symmetry causing dark patterns. This asymmetric approach redistributes the alignment effects to eliminate the cross-shaped dark patterns while preserving the four-domain alignment structure.

The patent changes the critical parameters of the photoalignment process: instead of using perpendicular exposure directions (90 degrees), it employs oblique exposure directions defined by specific angles (first angle and second angle) relative to reference directions. This parameter change in the exposure geometry fundamentally alters the interference pattern of UV light, reducing the area where alignment dark patterns form while maintaining the four-domain alignment configuration.

The patent transitions from a two-dimensional perpendicular exposure arrangement to a three-dimensional oblique exposure arrangement. By introducing angular dimensions (first angle and second angle) in addition to the spatial positioning of exposure regions, the patent creates a more complex exposure geometry that eliminates the formation of large-area alignment dark patterns while preserving multi-domain alignment.