Directional BLU for Full Resolution Field Alternative Auto-Stereoscopic 3D/2D and 2D/3D LCDs

摘要

Switching directional backlight units (BLUs) were designed and prototyped for full resolution field alternative auto-stereoscopic 3D liquid crystal displays (LCDs). The inherent switching characteristic of the backlight unit (BLU) in which two confronting illuminating light sources were mounted on the sides of a light-guide plate (LGP), was applied to build 2D into 3D and 3D into 2D in theLCDs. The design based on 2D concept required a uniform bilateral prismatic structure with a cross section of isosceles triangle on the back surface of the functional LGP. The structure of bilateral-prismatic LGP and two confronting illuminating sides led to an increase in double uniformity, i.e. for double-side illuminations, and a decrease in single uniformity, i.e. for single side illumination (2D as primary function of the display; 2D/3D). However, a design that was based on 3D concept required angle gradation for the unilateral prisms on the back surface of the functional LGP that led to an increase in single uniformity and a decrease in double uniformity (3D as primary function of the display; 3D/2D). Both switching concepts were used to display 3D and 2D on LCDs of small size handheld game devices and still cameras.