An effective light-extracting microstructure for a single-sheet backlight unit for liquid crystal display

A single-sheet backlight unit (BLU) for a liquid crystal display (LCD) with improved light extraction efficiency was developed. A new microstructure on the light-guide plate (LGP), namely a merged-dot pattern, is proposed. The effective emission area was significantly increased by using the proposed light-extracting structure, resulting in high light extraction efficiency. Through optical simulation, we investigated the effect of the enlarged emission area on the luminance and vertical light emitting performance of the single-sheet LGP. Then, in order to verify the simulation result, we fabricated a polydimethylsiloxane (PDMS) LGP containing the proposed light-extracting microstructure by using backside 3D diffuser lithography and the PDMS replication processes. The fabricated single-sheet BLU showed an average luminance of 4197 cd m⁻² with four 0.97 cd LEDs, corresponding to 27.8% enhancement over the LGP without the merged-dot patterns. (paper)