Ultra-thin design of direct-lit backlight unit

In order to reduce optical distance(OD)and realize ultra-thin design of direct-lit LED backlight module,this paper proposes a kind of diffuser plate with prism-based micro-structure on the bottom.The optical theoretical analysis is first performed on the prism-based micro-structure,which proves to be feasible to reduce the OD.The prism-based micro-structure is then practically tested and utilized in 81.3cm(32in)LED backlight.Experimental results show that the diffuser plate with prism micro-structure has effect on increasing the diameter of LED shadow by about 10%and reducing OD.The OD of the prototype with 32 in LED BLU is reduced from 13 mm to 11.8mm.Such diffuser plate with prism-based micro-structure can help to realize the ultra-thin design.