Modify 2D Gradient-Electrostatic-Forces to Manipulate Micro-Aspherical Lens for Small Form Factor DVD Pickup Head

This paper proposes a novel design concept and fabrication method of micro aspherical lens for DVD head. Gradient-Electrostatic-Forces (GEF) were employed to shape liquid polymer from hemisphere into parabolic or near cone shape, and the shape can be fixed by a UV curing process in situ while surface tension force in the edge of microlens is far bigger than electrostatic force. As a result, the lens focused light spot size (by red light 632.8 nm) was reduced from 2.302 mum into 0.778 mum, suitable for the need of objective lenses with high numerical apertures and resolution. Very high quality focus effects and 0.66 NA were obtained at an optimized shape of the GEF lens, which is compatible to those of the commercial DVD objective lens.