Optical Sheet Laminates for Backlight Units

The single print pattern is divided into multiple print patterns (first print pattern and second print pattern) formed on separate optical sheets or different surfaces. Each print pattern has a lower individual print density, which reduces the impact of misalignment while collectively achieving the desired luminance uniformity. This segmentation allows the system to tolerate positional deviations better than a single high-density pattern.

The invention changes the parameter of print density distribution by using multiple patterns with different densities rather than one high-density pattern. The first and second print patterns have lower individual densities that sum up to the required total density reduction, thereby reducing the sensitivity to alignment errors while maintaining the overall luminance uniformity improvement.

The total required print density is segmented across multiple print patterns. Instead of one pattern with high density and large tone changes, the invention uses multiple patterns with smaller individual density changes. This segmentation reduces the tone change magnitude in each pattern while maintaining the cumulative effect needed for luminance uniformity.

Each individual print pattern applies a partial reduction in light transmission rather than the full reduction required. By combining multiple partial actions (first print pattern and second print pattern), the system achieves the necessary total light reduction without creating excessive tone changes in any single pattern, thereby reducing misalignment sensitivity.