Mass-Producible Polydimethylsiloxane (PDMS) Frontlight Unit (FLU) for Reflective Displays

A new frontlight unit (FLU) that consists of a single-body light-guide plate (LGP) with cylindrical microstructures has been proposed as a light source for reflective displays. Owing to the material properties of polydimethylsiloxane (PDMS), the proposed FLU shows high transparency and flexibility. In order to fabricate the FLU with mass production-friendly processes, simple 3-D micromachining methods were developed using thick photoresist lithography and metal electroplating. Compared with commercial FLU products, the fabricated 6-in PDMS FLU showed good optical performance with an average luminance of 5.58 nit (cd/m²) and uniformity (minimum luminance divided by maximum luminance from nine positions) of 53% using four LEDs. The proposed FLU can be utilized as a built-in light source for diverse reflective displays applications.