Design and fabrication of variable micropattern for flexible backlight

The effect of variable micropattern for an advanced compound optical film was investigated. This compound optical film was made by using Lithographie galvanoformung abformung (LIGA)-like process. The multi-step electroforming with micro-void embedded Polydimethylsiloxane (PDMS) was developed. This work presents many innovative processes, such as the homemade gray scale mask to fabricate variable size array; the multi-step electroforming process to fabricate various fill-factor from high to low and from low to high; and the embedded micro-void to fabricate optical film without substrate that avoids total internal reflection. FRED is a commercial software for optical simulation and design. The diffusion of the micro-void array and light guide of the variable size microlens array were discussed. Experimental results show that the variable size microlens array with embedded micro-void can be packaged flexible on side light emitting diode (LED) to improve its lighting uniformity and the light extraction efficiency.